feature article – The Native Plant Gardener

Hate mowing lawns? Get rid of the grass!

Posted on September 3, 2024September 3, 2024 by ridgetownrick

Most people reading this article will have, at one time or another, faced the prospect of removing a section of lawn in order to create a new garden – whether that be specifically for a native flower bed, for a vegetable patch, or for some other good reason. Today I want to discuss some of the pros and cons of the various methods of getting rid of the grass that I have experienced in my quest to grow something besides lawn. In particular I will look at the following 5 methods…

Herbicides

The “Lasagna” Method

Tarp

Solarization

Removing the Sod (with shovel or mechanical sod lifter)

A sod free bed makes a great way to start a new garden.

Herbicide (Glyphosate)

Let me start this section with the confession that, in the early days of gardening, I DID use RoundUp (i.e. Glyphosate) to kill off the sod, but I no longer use this method (see *Note at the end of this article on my feelings about Glyphosate).

Roundup is very effective at killing sod. It is also very easy. The best part of it is that it is relatively quick – spray your patch of grass this weekend, and next weekend start lifting the dead sod (it can take up to 2 weeks for some of the plants to turn brown, but they will be dead. Glyphosate is drawn down into the roots of the plant via the sap stream in the leaves, where it prevents the roots from absorbing nutrients from the soil. The big advantage is that if you don’t dig out all the roots, it won’t matter.)

However, RoundUp is expensive, hard to get (in some cases), and carries a huge stigma. It also has the distinct disadvantage of potentially killing off good plants through spray drift. Another drawback is that if you accidentally step on a sprayed patch, you leave footprints of dead grass across your lawn as you walk back to the house. (Ask me how I know this – d’oh!) That makes it pretty obvious that you have used Glyphosate to anyone who visits (at least until the dead spots fill back in).

And, although the sod is now dead, you still have to rototill it up or dig it out before you can plant your new garden. I would only recommend this method if your patch of lawn is heavily infested with bindweed or some other equally deep-rooted invasive species that you won’t be able to easily remove with the other techniques.

The Lasagna Method

The lasagna method of gardening is often used in the preparation of vegetable gardens. This is because the materials used will create a rich, moisture retentive garden soil that may be too rich for native plants. However, if you are developing a garden in a new subdivision where all the topsoil has been removed, or on land that was once a gravel pit, this method might work for you.

The trick with the lasagna method is to lay down a layer of cardboard or newspaper first. This helps to smother the grass (these materials will decompose in a year or less and become part of the soil). You then cover it with layers (like a lasagna) of mulch, lawn clippings, compost, etc. to make a rich, fluffy soil to plant into. The process can take a year for the layers to break down enough to become soil, so it is a long term process.

This use of cardboard and woodchips to create a new vegetable bed works well if you have patience.

A great advantage to this method is that you don’t have to physically remove the sod. And you can plant right into the decaying mulch. (Don’t do this if the mulch is actively working and is hot – you could burn off the sensitive plant roots.)

The big disadvantage is that it can take the better part of the year to decompose enough to safely plant into – depending on weather, depth of mulch, etc.

Tarps, Old Carpet or Cardboard

Similar to the lasagna method, in that this method starves the sod (and weeds) of light and moisture, a tried and true way to kill grass is to cover it with some form of dark barrier. The main drawback to this method, if you’re an impatient gardener, is that it can take months to ensure the grass and weeds are all killed.

Cardboard will work, though it might be a tad of a challenge to keep it from blowing around or getting shifted from foot traffic. Adding some mulch to weigh it down brings you back to the lasagna method but, if your land is stony, you could use rocks to keep it in place. Cardboard will eventually deteriorate, and if you don’t plan to leave it in place and plant through it (cutting holes for each plant), then it can be pretty messy to lift for disposal.

I have used old carpet – someone had put rolls of it out for garbage pick up and I just scooped it up and took it home. If there is a carpet store near you, they will likely be glad to give you carpet they’ve ripped out of someone’s house – it will save them from taking it to the dump. The carpet was quite effective at killing off the grass under a large maple tree and it did not have to be weighed down with anything as it was quite heavy enough to resist any unwanted movement – especially after it had been rained on. The hard part was cutting up the old, smelly, rotting carpet to dispose of it – small chunks at a time – with my household garbage once it had done its job.

Laying chunks of carpet down to kill off the grass

Tarps work well. They have the advantage of being lightweight and easy to handle, and they come in various sizes (and colours). They do need to be weighted down (with stones or bricks) or pegged. The drawback is that they are pricey and UV rays will eventually break down the plastic if it is left in full sun for the better part of a year.

A much more frugal option is to go to your local lumber yard and ask for the plastic tarps that cover the lumber piles. These are normally just thrown in the garbage when a new shipment of lumber comes in. My local lumber yard chuckled when I asked if I could have a couple, but they gave them to me for free. If you’re lucky, you may get some that don’t even have rips or holes in them. And the bonus: you can cut them to fit any shape garden without worrying about ruining a perfectly good tarp.

The tarps that cover lumber are quite large and usually FREE

Like other methods of smothering the grass, you will probably have to leave the covering on the lawn for several months to effectively kill unwanted weeds. Some of the very persistent plants (like bindweed, etc) may even survive tarping – especially if they are well established in your lawn.

Some weeds like the bindweed circled in blue can be very persistent.

Solarizing

Solarizing is similar to the tarp method, but with the use of clear plastic sheets that magnify the sun’s rays to kill the grass. Proponents claim this can effectively kill off the sod in a couple of months. It is a method I have NOT tried, so I only have their word for it. Nor do I know how effective it is on those deep rooted weeds like bindweed. But if your future garden area is small, you can buy clear plastic (sold as vapour barrier in the hardware store) at a relatively reasonable price.

Shovel, Mechanical Sod Lifter

My preferred method of sod removal these days is a flat-bladed shovel. This is because I enjoy the physical aspect of digging, I have a flat-blade shovel (so it doesn’t cost me anything), and my soil is a nice sandy loam that is easy to dig.

My trusty flat bladed shovel has removed a LOT of sod from my yard over the years.

With my shovel, I simply dig a small v-shaped trench around the perimeter of the new garden bed, then shove the blade under the grass and flip it up. I then toss the sod clump into the wheelbarrow to be dumped (grass side down) in a back corner of the yard where the grass then dies – leaving a pile of topsoil for use when and where I need it. The drawback is that this is a slow process and can be very hard on the back. The good part is that you can dig out any deep roots as you come across them.

A slow but effect method for removing sod – and building muscles. It can be quite a workout.

I’ve never tried an actual sod lifter, either a manual one a powered one, but really these are just more sophisticated versions of the flat shovel. You can usually rent manual lifters or powered sod lifters, depending on your budget and the size of the garden area, at most of your typical tool rental places.

A manual sod lifter available from Lee Valley Tools

The End Results

Ideally your efforts will result in a garden that is free of grass and weeds, ready to plant into. You may have to rototill if you are in heavy clay soil or you may do like I did and simply add a layer of woodchip mulch to keep moisture and soil organisms in place, thereby letting nature loosen the soil for you. In the end, you should have a wonderful new garden bed that is ready to go.

Happy Native Plant Gardening.

PS – My Thoughts on Herbicide Use (this may be controversial for some!)

*Note – I do not have a problem with the judicious use of Glyphosate, in small amounts, for very specific plants – especially for invasive, poisonous or extremely deeply rooted plants (like bindweed). Round up is broken down in the soil by soil bacteria within a few days. The bacteria use it as a food source (Kanissary, et al., 2019). “Glyphosate’s half-life in surface waters after forestry spraying in Manitoba was less than 24 hours. In soils, glyphosate undergoes microbial degradation to the metabolite aminomethylphosphonic acid (AMPA), which is slowly degraded to carbon dioxide and simple inorganic compounds” (Gov’t of Canada, 2015).

For those who believe salt, vinegar and dish soap are a better option, I suggest you do some unbiased research. That home remedy will kill off the above-ground part of the vegetation only (it is a contact herbicide and works by killing whatever it comes in contact with), but not the roots, so most perennials will just re-grow. In the meantime, you will have poisoned the soil for microbes, earthworms, etc., killing off those important soil fauna (Enroth, 2020). If you believe that this is a chemical free way to kill plants, remember that salt is the chemical sodium chloride and vinegar is acetic acid, and in sufficient quantities to burn off plants, these chemicals will also kill soil micro- and macrofauna. Research has also shown that acetic acid in great enough concentration to effectively kill plants (5-10%) is “incredibly harmful to humans. Any contact with the skin and eyes causes irreversible corrosion and damage, meaning gloves and goggles are a must when using vinegar herbicides” (Enroth, 2020). In fact, even at these high concentrations of acetic acid it is really only effective at killing very young (less than 2 week old) seedlings and some young annual species (Smitth-Feola & Gill, 2022).

Equally as problematic, it will kill any frogs or toads it happens to land on (Enroth, 2020). For herbicides to be approved in the first place, they have to be shown to target only plants, usually by attacking specific plant parts at the cellular level, like the chloroplast which animals and other organisms lack. Neither salt nor vinegar are approved as herbicides because they impact both plants and animals that they come into contact with (Pelliccia, 2024). A good friend accidentally spritzed a toad while using the concoction. She noticed right away and washed the toad off, but it died anyway.

I am not condoning the wholesale use of herbicides to remove lawn. Quite the contrary. But if it is used carefully and in small quantities, it can be a very safe and effective solution for problematic weeds.

References

Enroth, C. 2020. Home Horticultural Remedies. University of Illinois Urbana-Champaign, Illinois Extension. https://extension.illinois.edu/blogs/good-growing/2020-05-22-home-horticultural-remedies

Government of Canada. 2015. Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Glyphosate. https://www.canada.ca/en/health-canada/services/publications/healthy-living/guidelines-canadian-drinking-water-quality-guideline-technical-document-glyphosate.html

Kanissery, R, Gairhe, B, Kadyampakeni, D, Batuman, O and Alferez, F. 2019. Glyphosate: Its Environmental Persistence and Impact on Crop Health and Nutrition. Plants. doi: 10.3390/plants8110499

Pellicia, S. 2024. Salt & Vinegar on Weeds? Save it for the Chips! Washington State University/Washington Dept of Natural Resources. https://foreststewardshipnotes.wordpress.com/2024/06/12/salt-vinegar-on-weeds-save-it-for-the-chips/

Smith-Feola, D. and Gill, S. 2022. Vinegar: An Alternative to Glyphosate? University of Maryland Extension, https://extension.umd.edu/resource/vinegar-alternative-glyphosate/

Native Plant Gardens: Naturalized or Formal – Which is Better?

Posted on July 31, 2024July 31, 2024 by ridgetownrick

We all garden to our own aesthetic. For some, green, sterile lawns of shortly mown grass is a beautiful sight. Others see beauty in lush beds of exotic (and often invasive) flowers, shrubs and vines. Increasingly, though, especially since Doug Tallamy’s groundbreaking work (if you haven’t read his book “Bringing Nature Home”, I urge you to do so), people are adding native species to the mix. Some are going so far as to remove all the non-native species and plant only native (and near-native) plants in their yards. They are doing this in an effort to provide food and habitat for the butterflies (and their caterpillars), bees, fireflies and other insects that are so important to a healthy environment.

But what gardening style is best for native plants? Today I will wax a little philosophical on this topic and offer some commentary on the ways we can garden with native species. There is no right or wrong way to do it – it all boils down to what YOU prefer.

The Formal Approach

At one extreme is what I call the Formal Gardens approach. This is often the direction taken by folks who have gardened for years with non-native species, in a Victorian style of gardening.

james denham, CC BY-SA 2.0 https://creativecommons.org/licenses/by-sa/2.0, via Wikimedia Commons

These gardens typically consist of distinct flower beds with low growing plants in the front and tall ones at the back. They are usually well weeded, with a layer of mulch (often wood chips) on the ground. Flowers and grasses are grown in distinct clusters within the beds. The general appearance is that of a “well tended garden” and displays a strict control over nature.

The big advantage to this style of gardening is that you are unlikely to raise the ire of neighbours who know nothing about native plant gardening, and consequently you are unlikely to get a visit from a bylaw officer telling you to mow down the “weeds”.

My own semi-formal gardens consist of distinct flower beds connected by grass “avenues”

In my southwestern Ontario garden, this is definitely the way I started (and to a certain extent, still garden). But my gardens are designed to teach – I have over 300 species of native plants, all clearly labeled so that visitors can see what the plants might look like in their gardens. I leave wide, grassed pathways so that groups can easily wander to observe the plants and easily view the different species. These semi-formal beds make for a park-like setting and, in my opinion, make for a very relaxing back yard experience.

The “Naturalized” Approach

At the other end of the spectrum is the “toss the seeds and let them grow” approach. After all, this is how Mother Nature does it. This method of gardening can seem very messy to the uninitiated and is the method most likely to upset neighbours – especially those who love their short-cropped lawns. However, with the right mix of plants, this natural approach can provide fabulous continuous colour and great year-round structure in the garden, and can potentially create the most habitat for pollinators and other insects. For those who grew up on formal gardens, it can take a while to wrap our heads around the value these “messy” gardens provide.

Unfortunately, not all municipalities appreciate the value of a naturalized garden of native plants and consider anything not grass to be weeds.
(https://lorrainejohnson.ca/blog/all-this-should-go-says-toronto-bylaw-officer)

Something in Between

I confess that as my formal style gardens mature and fill with lots of self-seeded plants, the formal beds increasingly take on the messier look of a naturalized garden. And I’m good with that. Rather than seeing mess (as I once did), I now see habitat. And I also see lots of butterflies, moths, bees, wasps and other beneficial insects. And now, when plants flop over in the bed, I don’t rush in and tie them up. Instead, I’m more apt to just let them flop. I find that as I get older, “lazy” gardening appeals more and more. (Also, with age, I worry less about what my neighbours think!)

A delightful semi-wild garden that follows traditional planting – tall at the back, short at the front – can be a beautiful compromise

Mass Planting

Whether you choose formal or “natural”, one strategy that can make for an impressive display is to make sure you plant LOTS of each species together. Not only does this increase the impact of the flowers when they’re in bloom, but it also makes it easier for specialist pollinators to collect lots of pollen from their preferred plants.

It’s Up to You!

Regardless of whether you want to garden with formal beds, with wild and natural, or somewhere between, the key thing is to continue gardening and introducing more native plants into your flower beds. How the plants are arranged is entirely up to you, but our insects, birds and other wildlife depend on us growing native species. (You can read more about this in last month’s article – “Why Native Plants”.)

Happy native plant gardening.

P.S.

If you are concerned about bylaw officers telling you to cut down your “weeds”, then please get involved in a very important movement spearheaded by well-known native plant author Lorraine Johnson, the Canadian Society of Landscape Architects, the Canadian Wildlife Federation, the David Suzuki Foundation and the Ecological Design Lab to get by-laws updated. You can check out the open letter to municipalities, and offer you support via this link.

The Importance of Growing Native Plants

Posted on June 29, 2024June 30, 2024 by ridgetownrick

Native plant gardening is one of the fastest growing sectors of horticulture in North America today. I started growing native plants 20 years ago, but I was not really an early adopter; there were lots of books written in the 70s, 80s and 90s about growing native plants. A good number of these are on my bookshelves.

One of the older books on gardening with native plants on my shelf – published in 1984.

We all start growing natives for our own reasons. Initially, for me, it was to add plants that I remembered from childhood growing up in a rural area. Our fields were full of these “weeds” that were quite beautiful. Imagine my dismay when I discovered that most of them were actually not native, but were, instead, garden escapes. These included things like chickory, mullein, goat’s beard, and teasel.

Common Chicory (*Cichorium intybus*) – a native of Europe

But the more I read and discovered, the more intrigued I became with those plants that were truly native to where I lived. And after a lifetime of gardening, I finally found a set of plants that I could get passionate about.

In the beginning, I suspect it was the novelty of growing something “different” that drew me. But as my gardens started to fill with native flowers, so my yard started to fill with butterflies, dragonflies, fireflies, hummingbirds and a wide range of fascinating bees, wasps, flower flies, and other important pollinators.

Did you know that 90% of insects develop ONLY on plants for which they share an evolutionary history – i.e. NATIVE plants?

Many of the people reading this will be familiar with Doug Tallamy’s work in the US showing that it takes 5-6000 caterpillars to successfully fledge a nest of Carolina chickadees. His work also showed that the adults need at least 70% native plants within their nesting territory to successfully fledge a nest of babies. He also showed that less than 30% native plants will result in the complete loss of the nest. We can probably safely assume that similar figures will hold true for almost all songbird species.

Why are caterpillars so important? For starters, caterpillars are soft and easy to digest. In addition, they contain more protein, ounce per ounce, than beef. In fact, caterpillars transfer more energy from plants to other species than any other animal. If we have no caterpillars, we will have failed food webs.

Interesting fact: 14% of our native plants support 90% of our caterpillars. These plants are referred to as Keystone Plants.

Non-native plants do not support the diversity of insects – caterpillars in particular – necessary to support the food web. If we grow mostly non-natives, we will have fewer bugs which means fewer birds. And 90% of plants require insect pollinators, so if we have fewer insects, we end up with fewer plants. And we need plants for oxygen, for food (directly) and for food indirectly (in the form of animals that eat plants).

North America has lost 3 billion birds in just the last 50 years. I wonder how much of that is the result of monoculture lawns and non-native gardens that result in no caterpillars for the baby birds.

You don’t need to replace all your non-natives with native species. But the more native plants you grow, the more you will want to grow – especially once you see the biodiversity that appears in your garden once you do.

Let’s grow more native plants, feed more caterpillars, bees and birds. We CAN make a difference, one garden at a time.

A Few Plants You Can Grow for Butterflies (Pictorial)

A Bigger List of Butterfly Host Plants

Butterfly-Host-table Download

On Buying Native Plants

Posted on June 1, 2024June 1, 2024 by ridgetownrick

When I started growing native plants back in 2005/2006, native plant specialty nurseries were few and far between, poorly advertised, and the selection of plants was quite limited. And unfortunately, most of those early native plant nurseries I frequented are no longer in business – some because they couldn’t afford to keep the doors open, some because the owner reached an age where retirement seemed a good choice.

In this month’s article, I’m going to talk a bit about native plant nurseries I have purchased from over the years and about the ones that are gone, the ones that survived, and the plethora of new ones that are appearing. All this is in anticipation of a new series of articles I plan to start later this month (in week 3) and will keep writing about each month as long as I can gather enough information. The series will be an in-depth look at Native Plant nurseries in the region. In the beginning these will be nurseries that I regularly do business with (there are lots!), but if the topic is popular enough I may try to expand to other nurseries as well.

A great selection of native plants at Golden Alexaander’s in Sarnia, ON

In the Beginning

Living in fairly rural Southwestern Ontario has its advantages and drawbacks. First off, I live in the Carolinian Life Zone (https://inthezonegardens.ca/ontario/) – one of the most ecologically diverse regions in Canada, and the region with the most species at risk – and the range of plants that are native here is amazing. The drawback is that, with low a population density it can be a challenge to support a niche market (like native plant gardening) with so few people to buy your plants. But a few early adopters tried and those are the nurseries that got me started.

Where I live, near Chatham, ON, is the heart of the species rich Carolinian Zone.

Lost Nurseries

I think the very first native plant nursery I visited was Wheatley Woods Native Plant Nursery and Garden Centre, just outside of Wheatley, Ontario. Craig had a nice selection of native plants and he was very helpful in getting me started down the right path. One of the big frustrations for Craig was that (to paraphrase him) little old ladies would come in and ask for hostas or begonias, or tell him they could get plants a lot cheaper at Walmart. Unfortunately, it would seem he was just a bit ahead of the native plant gardening curve and eventually closed down (as near as I can find out – he operated from 2005 to around 2016, or thereabouts – I moved to Manitoba in 2014, and when I returned in 2018 he was no longer in business).

Much closer to home, I used to also purchase native plants from a lovely little nursery just outside of Blenheim, ON (I don’t recall if the business actually had a name or not). Sherri’s is another business that disappeared while I was in Manitoba. In this case, I believe they sold their farm and moved on.

Yet another great native plant nursery that has gone by the wayside (owner retired) was Grand Moraine Growers near Alma, ON (1999-2019). Fortunately, Origin Native Plants in Guelph (https://www.originnativeplants.com/shop) took over the remaining inventory and has carried on the tradition. Unfortunately for me, I didn’t discover GMG until the year they closed, but I did make two trips there that year and loaded up the car. I now buy plants from Origin almost every year.

The final defunct nursery I’ll mention is another that I discovered in its last year of operation before the owner retired – Nith River Native Plants outside of Kitchener. Unfortunately I’ve not been able to find any information on the years that it operated. Graham had a fairly small greenhouse, but a wonderful selection of plants. But beyond that, I just loved the drive through the countryside to get to his place.

Still Going Strong

Despite the loss of a number of the early adopters, a number of those early nurseries are still going strong, and many, many more have opened their doors in the last few years. The demand for good quality native plants has grown tremendously in recent years, so with any luck these nurseries will be around for some time.

Very close to where I live is a small nursery tucked away in a forest. Heavenly Earth (https://heavenlyearth.ca/) originally specialized in trees and shrubs, but has branched out into perennials in the last few years. I’ve made many trips to Liz and Dale’s little hidden piece of heaven and come home with a trunk full of plants.

A little further afield for me is another survivor of the early native-plant-nursery extinctions – Not So Hollow Farm (https://notsohollowfarm.ca/) in Mulmur, ON (near Creemore, if that helps). Ian and Vicki also started with native trees and shrubs (around 2002) but have expanded to perennials, as well. They’re a little hard to find, but they have lots of beautiful plants. And the scenic drive there is worth the road trip alone even if you end up not buying anything.

One of my top 3 favourite nurseries has to be Grow Wild! Native Plant Nursery, Landscaping and Biological Consulting (https://www.nativeplantnursery.ca/) which has been around since 2001. Paul’s always got some very interesting species in his collection, though he primarily sells wholesale only. (I have a special affinity to this nursery because it’s located in the little village of Omemee, ON where I grew up through my later elementary school and all of my high school years.)

New Kids on the Block

Fortunately for all of us native plant enthusiasts, there are a number of new (and relatively new) native plant nurseries coming on stream these days. And they cover most of the southern Great Lakes region (on both sides of the border).

One of the newer establishments is Golden Alexanders (https://goldenalexanders.ca/) just outside of Sarnia, ON. This is another of my top 3 favourite nurseries. That’s because Nick has 2 emerald green thumbs and produces beautiful, healthy plants. He also has an amazing range of species available. He’s only open to the public on Saturdays because he’s busy doing landscape construction and maintenance the rest of the week. Golden Alexanders is the first nursery I will feature in my series of articles (in about 3 week’s time).

Some more great sources of native plants (all of which I have purchased from over the years) are Prairie Song Nursery and Restoration (https://www.facebook.com/prairiesongnursery/) in Walsingham, Thedford Native Plants (https://www.thedfordnativeplants.ca/) near Thedford, Ontario Flora (https://www.ontarioflora.ca/) near Markdale, and just over the border in Quebec not far from Ottawa is Beaux Arbres Native Plants (https://beauxarbres.ca/). There are many more – a few of which aren’t necessarily native plant specialty nurseries, but do carry a good selection of natives – and hopefully in the coming months I will be able to do articles on all of these sources, as well, plus many more.

I would be remiss to leave out the one of the most popular mail-order-only sources: Ontario Native Plants or ONP (https://onplants.ca/). And, increasingly, there are also excellent sources of native plant seeds, including BotanyCa (https://botanicallyinclined.org/) from which I have made a few purchases. These, too, are apt to be the subject of future articles.

In the meantime, check out my map of native plant sources throughout all of North America. (If you know of one that ISN’T on the map yet, please let me know so I can add it.) You can find that map at bit.ly/rixNPsources.

Nurseries and Garden Centers that not only sell, but actively promote their native plants. Also listed are some regular native plant sales locations (monthly or annual sales).

In the meantime, keep an eye out for my first Native Plant Nursery profile, coming soon.

Happy native plant gardening.

Building a Mini-wetland

Posted on April 30, 2024April 30, 2024 by ridgetownrick

As a native plant gardener in a small southwestern Ontario town, I am blessed to have a half-acre property with a variety of growing conditions. These range from dry, full sun to dry, full shade and from moist, full sun to moist, full shade, and pretty much everything in between. But of course that wasn’t enough, so in 2012 I brought in 40 tons of Manitoulin Island limestone and built an “escarpment”, complete with a waterfall. (This will likely be the subject of a future article – or two). After I retired in 2018, I added a bog garden (see my Dec 2022 article The Boggy, Boggy Dew – the story of Creating a Bog Garden) at the base of the falls. In that article, I lamented that in my impatience to get plants established, I planted a number large, aggressive wetland plants that were overwhelming the delicate bog plants the garden had been designed for.

An overcrowded bog garden at the base of the falls.

In 2022 I decided to rectify that problem by building a “wetland” in my back yard – a place I could put all those tall, aggressive spreaders. This is the story of that project.

What is a Wetland?

In Canada (the US has similar definitions) “wetlands are submerged or permeated by water – either permanently or temporarily – and are characterized by plants adapted to saturated soil conditions” (Government of Canada). There are 4 main classifications of wetlands, defined primarily by the source of water. These are Fens and Bogs (defined in my previously mentioned article) and Marshes and Swamps. Marshes and Swamps differ mainly in the vegetation type – Swamps are treed wetlands while Marshes have little or no woody vegetation. Because its size precludes planting trees, I guess my wetland could be considered to be a Marsh.

Where to Start?

As my yard fills up with various flower beds, it is increasingly challenging to find room to create a new feature. I decided to create the wetland near the back of the property, which is about a 6 foot drop below the level at the front. This would allow me to run water via gravity to the wetland during periods of drought.

But, in order to have a large enough area, I had to remove half of the very first flower bed that I built (back in 2005). That, of course, necessitated first creating a new flower bed to move all those plants to. Because of weather conditions, that ended up being a much longer project than anticipated, and delayed the start of the wetland by a year. But in the spring of 2023 I was ready to begin.

This section of my original flower bed had to to to make room for the wetland.

My first step was the design. Originally I wanted to incorporate a pond into the wetland, but soon realized that in the small space available this would not be feasible without a lot of engineering. I needed to keep it simple.

The original concept incorporated a pond into the wetland.

In the end, I opted for a two-phase project – a wetland and an adjacent pond. (The pond was supposed to go in this year, but other projects have taken priority so it may not happen till late this fall or some time in 2025.)

Digging the Hole

Then came the “fun” part – digging the hole. There was a lot of dirt to move, and tree roots to work around, but fortunately no stones bigger than a chicken egg (I love my soil!). The hole would be about 170 sq ft and 3’ deep for a total volume of soil of almost 20 cu yards. According to the internet, this weighed somewhere between 10 and 20 tons. (No wonder I had rippling abs by the end of the project!!)

My soil is a sandy loam with excellent drainage, to it was pretty obvious I was going to need to put in some sort of rubber or plastic liner to keep the water from simply draining away. Because I was starting this in the early spring, none of the pond supply places near me had large rolls of pond liner. But a friend came to the rescue – they had an extra piece of plastic tarp used to cover silage on the farm just sitting up in the barn collecting dust, and they graciously donated it to the cause.

Filling in the Hole

Once the liner was in place, I needed a way to make sure the water was distributed through the entire area, but with every option I considered – from “big O” pipe to solid pipe – I ran into the concern of roots plugging the pipe. Even though there would be no tree roots, and I felt that most of the wetland plants wouldn’t reach a meter down with their roots, I couldn’t be sure. So I opted to at least wrap the perforated pipe in a heavy duty landscape fabric.

The landscape wrapped pipe in the bottom of the hole

Then it was simply a matter of putting all the dirt back in the hole and waiting for a few good rainfalls to settle the soil (which it did – a couple times) and then topping it back up.

What came out of the hole had to all go back in.

A few years ago, when a neighbour moved away, I bought several bags of fine peat moss from him that was left over from when he had put in a swimming pool (it had been used, instead of sand, under the pool liner). I spread this about 4-6” deep over the surface and rototilled it in to add some organic matter and water holding capacity to the soil.

Bringing Water

The next step was to bury a 2” pipe from the house to the new wetland. Even though the hole was lined and would hold water, we had a couple of very dry years in a row and I wanted a way to supplement the rain in the event of a drought – without having to drag 150’ of garden hose to the back of the property. Of course, with trees and flowerbeds all through the lawn, I couldn’t lay the pipe in a straight line, though I did dig the trench through one of the flowerbeds rather than go around it.

Laying the pipe was actually one of the hardest parts of the job as it had to be fed under existing pipes and utilities.

It holds water! Even before the water line is connected, a good rain saturated the soil

Filling With Plants

Digging the plants out of the bog garden and replanting them into the wetland turned out to be a hot and sweaty job – but fortunately a friend dropped in to help. We got everything moved in an afternoon, and there was even room for some new additions.

The moisture loving plants I have in the wetland so far are:

– Spotted Joe Pye Weed (Eutrochium maculatum)

– Sweet Joe Pye Weed (Eutrochium purpureum)

– Water Avens (Geum rivale)

– Southern Blue Flag Iris (Iris virginica)

– Cardinal Flower (Lobelia cardinalis)

– Seedbox (Ludwigia alternifolia)

– Prairie Loosestrife (Lysimachia quadriflora)

– Monkey Flower (Mimulus ringens)

– Royal Fern (Osmundus regalis)

– Ditch Stonecrop (Penthorum sedoides)

– Dark Green Bullrush (Scirpus atrovirens)

– Ohio Goldenrod (Solidago ohioensis)

– Riddell’s Goldenrod (Solidago riddellii)

– Bog Goldenrod (Solidago uliginosa)

– Purple Stemmed Aster (Symphyotrichum puniceum)

– Marsh Fern (Thelypteris palustris)

And a couple of volunteers from nearby gardens:

– Cut-leaved Toothwort (Cardamine concatenata)

– Yellow Jewelweed (Impatiens pallida)

– Black-eyed Susan (Rudbeckia hirta)

The first spring – lots of plants coming up. (Photo taken Apr 30, 2024)

Now I just have to wait till they grow and fill in the wetland, and find out if there will be room for some others. In the meantime, it’s back to some of those other projects.

Cheers,

Rick

Is it Invasive or is it just Aggressive?

Posted on March 30, 2024March 30, 2024 by ridgetownrick

Canada Goldenrod (*Solidago canadensis*), often mislabeled as “invasive”, is not. It is simply an aggressive native plant. There are strategies that you can use to grow this pollinator magnet even in a small garden.

This article is NOT about invasive species, but is about the strategies I use to deal with aggressive species in the garden. But first, a note about invasive species.

Common Reed or Phrag (Phragmites australis), Lily of the Valley (Convallaria majalis), Japanese Knotweed (Reynoutria japonica), Garlic Mustard (Alliaria petiolata), European Buckthorn (Rhamnus cathartica) – these names tend to strike fear (or at least dread) into hearts of native plant gardeners. They are all invasive species.

What makes them so bad? All were introduced into gardens from which they then escaped into the wild. There, their ability to spread was so powerful that they soon started to exclude the local plants (and sometime even animals).

Invasive species may spread by seed (e.g. Garlic Mustard, Phragmites, Buckthorn) or by rhizome (Japanese Knotweed, Lily of the Valley) or both. Control of the spread is difficult, at best.

Definitions

In the US, the USDA National Invasive Species Information Center (https://www.invasivespeciesinfo.gov/what-are-invasive-species) defines an invasive species as a species that is:

1) non-native (or alien) to the ecosystem under consideration and,

2) whose introduction causes or is likely to cause economic or environmental harm or harm to human health.

This harm often arises because the plant (in this case) either spreads so prolifically as to exclude all or most other plants, or it uses chemical warfare to eliminate any competition.

In Canada, the Invasive Species Centre (https://www.invasivespeciescentre.ca/learn/) states that invasive species “kill, crowd out, and devastate native species and their ecosystems”. It goes on to state that

“A species in considered invasive when:

It is introduced to an ecosystem outside of its native range, and

It has potential impacts on the ecology, the economy, or society in its introduced range.”

They also point out that in order for a species to become invasive, it must “possess the ability to outcompete and overwhelm native species in its introduced range.”

Thus, an invasive species is one that is an aggressive spreader. And though we have many native species that are aggressive spreaders – Canada Goldenrod (Solidago canadensis) comes to mind – these plants are not considered invasive because they fail to meet the first criterion of an invasive species – they are not introduced to the ecosystem. They belong here.

The analogy I like to use is that if a foreign military power attacked one of our cities and did a lot of damage – we would say they had invaded us. But if our own military did the same damage, we wouldn’t say they had invaded (because they belonged here) but that they were, instead, being very aggressive.

Aggressive Native Plants in the Garden

Seed Spreaders

In my southwestern Ontario garden, with its soft, loamy soil, a number of plants behave rather aggressively. Some of these, such as Silphium perfoliatum (Cup Plant) and Rudbeckia laciniata (Green Headed Coneflower), self-seed prolifically. These garden bullies provide great shows in the summer, but tend to outcompete everything else. The only thing I might do to control them is cut off the seed heads before the seeds ripen. Except I don’t do this because I want the seeds to provide winter nourishment for the birds. So instead, I spend a fair bit of energy and time each spring thinning out the excess plants. (These get potted up and planted elsewhere, or are sold to others so I can buy more plants.)

I have a number of other plants that also self seed prolifically, but they are welcome in the garden because they tend to play nice with others. These include the lovely little Pale Corydalis (Capnoides sempervires), Joe Pye Weed (Eutrochium maculatum), and a couple of milkweeds – Butterfly Milkweed (Asclepias tuberosa) and Swamp Milkweed (A. incarnata). Although they pop up all over the yard, they are not aggressive like Cup Plant so I generally welcome their spread.

Rhizome Spreaders

The other way plants spread aggressively in my yard is by rhizome – underground “roots” that pop up plants where you least expect them. These tend to be the more troublesome group. Some of these plants, like Canada Goldenrod (Solidago canadensis) and Star Flowered Solomon’s Seal (Maianthemum stellatum) can produce such a dense mat of roots that they eventually begin to exclude many of the other plants. These are the real trouble makers. But I have found a way to keep these aggressive spreaders in check.

Star Flowered Solomon’s Seal (*Maianthemum stellatum*) makes a great, dense ground cover, but it thick root mat excludes most other plants. I’ve often thought this would be a great plant for bank stabilization.

Vines and Vine-like Plants

Not all aggressive plants spread by seed or rhizome. A couple spread by above ground runners, too. Wild Grape (Vitis spp) and Virginia Creeper (Parthenocissus quinquefolia) are two fairly aggressive woody vines that can quickly cover fences or trees if allowed to spread. Fortunately, an quick annual pruning is all that’s needed to keep them in check.

A perennial, vine-like plant that likes to take over garden spaces is the lovely Virgin’s Bower Clematis (Clematis virginiana). It seems that every leaf-node that touches the ground on this rapid growing and sprawling plant wants to set down roots and sprout a new plant, which then sends out its own runners (stolons) which do the same. My Clematis grows along the fence that bounds one of my flower beds. Each spring I have to follow the runners throughout the flowerbed and pull up dozens and dozens of plants. Fortunately, these are readily potted up for resale so I can buy even more plants (or to give away if you’re not as mercenary about it as I am).

Virgin’s Bower Clematis – covering the fens and some Bee Balm

Controlling the clematis is a challenge in my garden because I like the look of it sprawling along the fence. If I wanted to keep it under better control, I would simply plant it in front of a trellis and prune it to stay there.

Controlling the Spread of Rhizomes – Root Barriers

My first root barrier was for Purple Flowering Raspberry (Rubus odorata). I was warned that these shallow rooted shrubs send out a lot of rhizomes, so I purchased a length of aluminum from a company that makes eavestrough. (They were installing new eavestrough on the house across the street so I just went over and asked if I could buy some.) This allowed me to “fence off” a large area.

It took many years before the leaf litter and wood chips got deep enough to allow the roots to go over the barrier. A little maintenance once every few years would have prevented this, but where it was growing I wasn’t too worried about it. And it’s definitely an easy fix if I decide to bring it back under control.

In order to keep plants more contained, I now grow all my aggressive spreaders in a large pot in the ground – in my case I use half of a plastic 45 gallon barrel, sunk into the garden. The barrels are cheap – you can usually pick up one for $10-20 (which gives you two pots). Sometimes you can even find them for free as I did when I volunteered to help clean up the river bank with our local conservation authority.

After cutting the barrel in two, I then drill some 1” holes in the bottom for drainage. I dig out a hole deep enough so that only about 1” of the barrel is above the ground, set the barrel in, then put the soil back in. (This is a great opportunity to amend your garden soil if, for instance, you are putting in an acid soil loving shrub, of if your soil is heavy clay and your plant wants a sandy loam, etc.)

I planted my Jerusalem artichokes in a half barrel 5 years ago. It has never escaped. And each fall I simply harvest as many of the tubers as I find – I always miss a few tiny ones – and the next year these missed pieces become a new crop.

Jerusalem Artichoke – imprisoned in its barrel has never spread

If digging a 3’ by 3’ hole in your yard is more than you can handle, I have successfully grown Common Milkweed and Grass-leaved Goldenrod in a large plastic pot – the kind small trees often come in. They’re only about 12-16” tall and a foot across. The plants grew in them for years.

Grass-leaved Goldenrod has shallow roots that can travel 6′ or more before sending up a new shoot.

A List of Troublemakers

The list below is by no means comprehensive, but it includes those that are the worst offenders in my garden for spreading by rhizomes. These are plants that need a lot of room to spread and may not be suitable for smaller garden spaces unless their control is kept in check with some form of root barrier. (Listed in alphabetical order by scientific name.)

Canada Anemone (Anemonastrum canadense)

Common Milkweed (Asclepias syriaca)

Virgin’s Bower Clematis (Clematis virginiana)

Grass-leaved Goldenrod (Eurybia divaricata)

Jerusalem Artichoke (Helianthus tuberosus)

Star Flowered Solomon’s Seal (Maianthemum stellatum)

Obedient Plant (Physostegia virginiana)

Prickly Gooseberry (Ribes cynosbati)

Smooth Wild Rose (Rosa alba)

Purple Flowering Raspberry (Rubus odorata)

Canada Goldenrod (Solidago Canadensis)

Prickly Ash (Zanthoxylum americanum)

Common Milkweed growing unchecked in another garden. The red line shows the string of new plants popping up from the original.

If you really want to contain the spread of your plants, you can use an old bathtub. Bulblet ferns are not aggressive spreaders – I just like the look of the old bathtub.

You CAN grow many of these aggressive plants in a small space without them getting out of hand. I hope these suggestions help you grow some of the lovely native plants we have that you haven’t grown before because of their aggressive nature.

Happy Native Plant Gardening.

On Writing a Book

Posted on February 29, 2024February 29, 2024 by ridgetownrick

March 1, 2024 is an exciting date for me. This is the release date of my book The Gardener’s Guide to Native Plants of the Southern Great Lakes Region. I thought that for this month’s article I would share a bit of what it took to get this book to publication.

The Original Idea

I started growing native plants in my yard around 2006. As with many native plant gardeners I’ve met, the process got off to a slow start. I knew nothing about our native species and, as many do, I soon learned that “wildflower” was not the same as “native” and that many of our wildflowers were actually garden escapes of European origin. What I really needed was a book to help me figure it all out.

One of my first books was Lorraine Johnson’s fabulous 100 Easy to Grow Native Plants for Canadian Gardens (Whitecap Books, 2005). With lovely photos and vital statistics about each plant, it was a fantastic jumping off point on my journey. I soon found, though, that many of the plants in my little book weren’t actually native to where I live, so I started buying more books on the subject. (I now have over 20 feet of bookshelf space dedicated to nature – most of which are directly or indirectly related to native plants and native plant gardening!)

The more I read, the more frustrated I became that I couldn’t find everything I needed in a single volume. Some books provided great growing information, some had wonderful photos of flowers, some had images of the seedhead and leaf, others had great anecdotal information about the ecology of the plants, but none seemed to have it all. And only one (Gisèle Lamoureux’s Flore printanièr [Spring Flora] – published by Fleurbec in Quebec and written in French) provided any kind of native range maps. I wanted to know if the plants I was about to add to my garden were actually NATIVE to my area, not just somewhere in my province.

The Inspiration

Then, around 2015, I bought a copy of Manitoba Butterflies: A Field Guide (I was living in Manitoba at the time) by Simone Hebert Allard and published by Turnstone Press (you can read my review of the book at https://www.amazon.ca/gp/customer-reviews/R39JQA3T4VPF1Y?ref=pf_ov_at_pdctrvw_srp). That’s when the lightbulb came on. This was the format that a book for native plant gardeners needed to have. A two-page spread for each plant, photos of the plants showing the leaf, the seedhead, the flower, and of the whole plant (ideally in a garden setting). But, critically, it also should have a detailed map of WHERE the plant was native. After all, native plant gardeners want to know if the plant they are growing is actually native to where they live.

Research, Research, Research

When I started putting together the book, I started by simply using the spreadsheet I had created that listed all the plants I was growing in my own garden. By that time, I had over 200 species of native and near-native plants. I created a file folder for each plant and then systematically began putting everything I could find into each plant’s respective folder. This included photos, maps, scientific journal articles, and a page of links to various websites.

I then created a template of the information I thought was needed in such a book. I started to sift through the thousands of documents I had and fill in the blanks in each plant’s template page. This template grew as I added more sections, then shrunk again as I removed some which, for various reasons, we decided to leave out (edibility and medicinal uses, for example, were two we eventually removed).

Collaboration

I spent about 3-4 years working on this project in my spare time. By this point, I had a mostly complete template page for about 230 species. I had no problem filling in the blanks for each plant from my research – information like plant height and width; flower colour; soil, sun and moisture needs; propagation; and so on. I realized that the book also needed a description of the plant to help people with more detail than you might see in a photo, and a description of the plant in the garden. But by this time I was running out of enthusiasm. It had been a solo effort that consumed almost all of my free time, often working late into the nights.

That’s when I was inspired by an article I read by Shaun Booth. Shaun ran In Our Nature, a native plant nursery and ecological garden design and construction business in southern Ontario. He also launched the Ontario Native Plant Gardening group on Facebook (which now has close to 25,000 followers). I asked Shaun if he would be interested in writing up the plant description parts and he said yes.

Bringing Shaun into the project launched a 2 year partnership that rekindled my enthusiasm for the project. It gave me someone knowledgeable to bounce ideas off of and, like me, Shaun believed the book was necessary.

Getting the Picture

Both Shaun and I have been photographing flowers in our gardens and in the wild for many years. But it soon became apparent that if we were going to use our own imagery in the book, we were going to need a lot more pictures than what we had (and, believe me, we had LOTS!).

We quickly realized that we both photographed primarily the flowers. We were missing examples of the leaf and seedheads and of the whole plant in the garden for many species, and that meant we had to go back to the start and make a list of what we were missing then try to get those shots.

While we pursued a publishing contract, we spent a lot of time getting those images. But just in case we couldn’t get good photos, we also started to approach folks who had posted the images we needed on iNaturalist and other sites. And almost every single person we approached agreed to let us use their image. Many didn’t even want the photo credit (but if we used their photo, we certainly gave credit). In the end, we managed to take most of our own pictures, and I want to acknowledge our heartfelt gratitude to all those who offered up their images.

Making the Maps

Mapping the native ranges for the plants was a whole other adventure. Fortunately, my background is in Geographic Information Systems (GIS) and making maps is what I did for many years. However, as I say in the introduction in the book:

“The maps in this book have been generated using all the information we could find online and through scientific journals and other publications. Some species, such as the goldenrods and asters, have been studied extensively in Ontario and elsewhere, and their native range is reasonably well documented. For many plants, however, there is little information available at an appropriate scale. In some cases, multiple sources provided similar ranges, which made mapping easy. However, in a few cases the range maps were so different that I wondered if they were even talking about the same species.”

Fortunately, we also had the fantastic support of ecologists and state botanists who graciously looked over the maps and pointed out any egregious misinterpretations we might have made. The result is that the book contains a map for each plant that shows its approximate native range in the southern Great Lakes region.

Finding a Publisher

Finally, we were ready to publish. That process was a long and challenging one. In Canada, the process for getting a non-fiction book published is very different than for publishing a novel. The industry standard is to produce a multi-page proposal that outlines what the book is about, provides examples of the content, compares it to books already on the market (the competition) and explains why your new book is needed. It requires references, ideally from other authors (which means they must read it first), and then you must show the publisher how you are going to help them promote and get sales for your book.

In our case, we sent proposals to half a dozen publishers over the period of a year (in North America, publishers, more often than not, don’t even respond if they’re not interested, and if they do it can be months later before you hear from them).

Finally, in frustration, I put together a mock up of what I envisioned the plant pages would look like and posted to various native plant gardening groups on Facebook, asking if something like this would be of interest. I was overwhelmed with the response. In 3 days, over 600 people got back to me saying they would definitely buy the book – in some cases saying they wanted multiple copies.

One person who saw my post, Carol Pasternak, already had a book published by Firefly Books and asked if I wanted her to show the concept to her publisher. I did, so she did, and the publisher liked what they saw, and within a week we had a contract offer.

Once the contract gets signed, you work with an editor to polish the book. The editor I worked with at Firefly was amazing. I found the process informative, extremely helpful, and working with Julie (my editor) was a wonderful experience. We had a couple of “creative differences” during the process, but were able to quickly come to a satisfactory compromise. The result is a book that looks great and that I hope gardeners will find to be extremely useful.

Some images from the book:

Next Steps

By the time you read this, the book should be available at bookstores and through online sellers. The book covers 150 plants but, if you remember, at the beginning I said I had about 230 species on my list. I was informed, and rightly so, that 230 plants (at 2 pages per plant) would make a volume that was large and unwieldy and very costly to produce (and therefore expensive to buy). That means that I’ve already got close to 100 plants ready to go for a volume 2, if demand warrants. Hopefully you’ll find this book to be a valuable addition to your library.

I will soon be on the road promoting the book at speaking engagements and doing book signings throughout the region – my calendar is already beginning to fill up. But I am proud of the new book. It’s the book I wish I had when I started gardening with native plants.

Happy Native Plant Gardening!

The Versatile Fern

Posted on January 31, 2024January 31, 2024 by ridgetownrick

Ostrich Fern (*Matteuccia struthiopteris*) growing under Sugar Maple (*Acer saccharum*) trees in my southwestern Ontario garden.

They don’t have big showy flowers (or even tiny inconspicuous flowers), they don’t feed pollinators or even rabbits (usually), and only a few seem to be host to some moth caterpillars, but it is my firm belief that every native plant garden should have ferns.

There are native ferns for just about every garden condition in the Southern Great Lakes region. After all, according to the Peterson Field Guide to Ferns of Northeastern and Central North America, “some 11,000 different species of ferns and fern relatives… occupy every corner of Earth, from mountaintops to deserts to coastal swamps.” That book covers over 100 species that are mostly native to our region. There WILL be a fern that will grow in your garden.

In this month’s article I will take a look at some of the ferns I have in my own garden in southwestern Ontario (as well as a couple I don’t have) and I will discuss why I like them. I have at least 18 species of ferns in my gardens – I have had more in the past, but lost a few over the last couple of years due to changing conditions in my yard.

My Top 10 Ferns

The following ferns are ones that just about anyone can grow in their gardens. They tolerate a wide range of soil moisture and/or light requirements and are long lived. (The plants are listed alphabetically by scientific name.)

Maidenhair Fern (Adiantum pedatum) – If you have a moist, humusy, full-shade garden, there are few ferns that add as much delicate beauty as the clump forming Maidenhair Fern. Also known as the Northern Maidenhair Fern, the Five Fingered Maidenhair Fern or simply the Five Fingered Fern, these ferns will tolerate some sun, providing they are kept moist.

This deciduous fern has black, shiny stems that reach up from a creeping rootstock to form a horseshoe-shaped semi-circle of horizontal bright green fronds. Maidenhair Ferns can get up to 3’ tall, but more commonly tops out around 18-24”. This is, apparently, one of the most sought-after native ferns at garden centres, and for good reason. An excellent choice for a full shade rain garden or bog garden, it regularly gets oohs and aahs from visitors to my yard. My only wish is that it would spread a little more aggressively – it seems to take forever.

Lady Fern (Athyrium filix-femina) – A gorgeous 2-3’ tall fern that gets as wide as it is tall, Lady ferns provide a delicate lacy look to the flower bed. This fern prefers dappled shade and moist to mesic conditions in any loose loamy soil, but will tolerate a fair amount of morning sun and I have seen it growing in full shade in forests.

Lady Fern (*Athyrium filix-femina*) sporangia

I have a robust specimen that anchors the corner in a shady garden. Small offsets form at the base, allowing this fern to spread – albeit VERY slowly. My specimen is close to 15 years old and is less than 2’ across at the base, but its full bushy nature makes it look much larger.

Bulblet Fern (Crystopteris bulbifera) – If I had to pick just one fern to grow in my garden, it would be this one. In early spring, the bright red stalks are very showy. The fronds will get quite long (up to 30”), but they tend to flop over and, in my garden at least, seldom get higher than 12-18”. They do work well in planters, though, providing a lovely cascading effect.

The plant gets its name from the tiny “bulblets” that grow on the underside of the fronds (in addition to the typical sori – groups of spores – that are found in ferns). These bulblets fall to the ground where, if the conditions are suitable, a new fern will spring up.

Bulblet Ferns – which have a number of common names including Bulblet Bladder Fern, Bulblet Fragile Fern, and Berry Bladder Fern – are a garden winner in many regards. In a low, moist area of my yard, these tiny ferns grow in full sun and maintain a reddish brown tinge throughout the summer. But I also have them growing in full shade in an old claw-foot bathtub, where I never water them and even in the driest years they have stayed green and fresh looking all summer long.

Bulblet Ferns cascading over the side of the bathtub

Crested Wood Fern (Dryopteris cristata) – New in my garden this past year, I’m loving the delicate look of this little (1-2’) clumping fern. It prefers part to full shade, but will even grow in full sun if sufficiently moist. It spreads slowly by short creeping rhizomes and, given sufficient time, can produce a nice, dense groundcover.

This fern is considered semi-evergreen as the fertile fronds tend to collapse during the winter, but the sterile fronds remain green all winter long. Also known as Buckler Fern, Crested Shield Fern, or Narrow Swamp Fern, this is a good choice for loam to clay soils.

Ostrich Fern (Matteuccia struthiopteris) – At up to 4’ tall when mature, this fern is super easy to grow in clay to sandy loam, full shade to mostly sun (with sufficient moisture) – though dappled shade is best – and dry to seasonally wet soil. In very dry soils, such as under a Sugar Maple tree, it may go dormant partway through the summer. It tolerates flooding in the spring so is ideal for that low spot where the snow meltwater collects.

Ostrich Fern (*Matteuccia struthiopteris*) flourishing in a moist, part shade garden.

It is a slow but persistent spreader and may not be suitable for small gardens. Ideal companion plants are Virginia Bluebells (Mertensia virginica), Trilliums, and Bloodroot (Sanguinaria canadensis), all of which bloom then begin to fade away just as the Ostrich Fern begins to fill out. Oh, and the unopened fronds are the edible fiddleheads you can find in specialty grocers in the spring.

For me, a key identifying feature is the badminton shuttlecock (“birdie”) form of the plant.

The distinctive “badminton birdie” leaf configuration of Ostrich Fern.

Sensitive Fern (Onoclea sensibilis) – Sensitive Ferns are not particularly drought tolerant but they will do OK in average garden soils as long as they aren’t allowed to get too dry. They do prefer consistent moisture. Their strength, though, is that they tolerate full shade to full sun, though they may turn yellow without a bit of protection from the afternoon sun. In my garden, these ferns rarely get taller than 2-3’, though the literature suggests they will get up to 4’ tall. They tolerate most soil types, from sandy loam to clay.

Sensitive Fern (*Onoclea sensibilis*) *growing* in full sun

They will form dense colonies but don’t spread as quickly as Ostrich Ferns and make a great ground cover in moist, partly shaded areas. Their woody-like fertile fronds persist through the winter and provide interest in the garden year-round. They get the moniker “Sensitive” because they are very sensitive to frost.

Royal Fern (Osmunda spectabilis formerly O. regalis, the latter name now reserved for the European species) – Royal fern is one of the tallest ferns we have, reaching up to 6’ in rich, moist to wet soils in full to part shade. It can even take periods of standing water. It very wet conditions, it will even tolerate full sun.

Royal Fern (*Osmunda spectabilis*) Photo Credit: R. A. Nonenmacher, CC BY-SA 4.0, via Wikimedia Commons

I’ve been growing this in less than ideal conditions for the past 5 years and my plants rarely get over 3’ tall, but this past summer I built a mini artificial wetland and moved some to that area. I’m hoping it will take off next year in its new home.

The leaflets of Royal Fern look a bit like a locust tree or a vetch, and its size makes it more shrub-like than what we typically think of a fern. Fronds typically turn yellow to brown in autumn. Spores are located in brown, tassel-like, fertile clusters at the tips of the fronds, thus giving rise to the additional common name of flowering fern for this plant. Osmunda fiber used in the potting of orchids comes from the fibrous roots of these ferns.

Smooth Cliffbrake (Pellaea glabella) – Difficult to find, and very fussy about its growing conditions, but if you have large limestone rocks in a lightly shaded area (or full sun, if moist), these tough little ferns are worth seeking out. They are a very small fern, only getting from 1” to 15” tall, but they will grow out of seemingly soil-less rock so they don’t have to worry about competition.

Smooth Cliffbrake (*Pellaea glabella*) growing on my very dry, artificial “escarpment” in southwestern Ontario

They are found on limestone cliffs in full sun to part shade. In appropriate conditions, this hardy little fern is evergreen, but here in my southwestern Ontario garden, growing on a dry “escarpment”, it turns brown and looks completely dead in the winter – though the fronds remain. With the first mild wet weather, the fern perks right back up and turns green again. The same thing happens during a summer drought. More than once I was sure the fern was dead, and then a nice rainy day brings it right back to life. It is an extremely slow grower.

A close cousin, Purple Cliffbrake (Pellaea atropurpurea), can be differentiated as it has a hairy stem instead of a smooth one. It is also much rarer (considered vulnerable in Ontario and imperiled in Michigan).

Purple Cliffbrake (*Pellaea atropurpurea*) growing in a crevice on limestone alvar, Manitoulin Island (with Poison Ivy – *Toxicodendron radicans*).

Christmas Fern (Polystichum acrostichoides) – This long-lived (15 years, or more), medium sized fern (18-24”) is one of only a handful of native ferns that is evergreen – retaining its shiny green leaves right through to the spring. They do flatten down in the winter, but still provide shelter for small birds and mammals, and nesting materials in the spring.

A forest floor inhabitant, it prefers moist, full shade, but will tolerate dappled sunlight if kept moist. They don’t do well in heavy clay soils, but they don’t mind pretty much any other soils, including average garden soil where a weekly watering will keep them green and healthy. Once established, they will tolerate periods of drought and would make a good filler plant in a shady rain garden.

Christmas Fern fronds unfurling in the spring

Easily recognizable in the winter (because it’s evergreen), a simple way to recognize Christmas Fern in the summer is the “thumb” on the individual leaflet (see image below).

The distinctive “thumb” on Christmas Fern leaflets.

Marsh Fern (Thelypteris palustris) – This low growing (6-12”), sun loving fern is great in a bog garden, a rain garden, or any other place where it can be kept moist (though it doesn’t like standing water). The delicate leaves can form dense mats, which help to provide necessary cool shade for the roots of things like Showy Lady’s Slipper orchids (Cypripedium reginae). This fern prefers rich, acidic, sandy loam but will survive in just about any garden soil, as long as it is moist. For a fern that is so delicate looking, it really is a tough plant. Other names for this fern are Marsh Shield Fern, Northern Marsh Fern and Eastern Marsh Fern.

Marsh Fern (*Thalypteris palustris*) in the garden

Marsh Fern doing its job to keep the roots of my Showy Lady’s Slipper (*Cypripedium reginae*) orchids cool in this full-sun bog garden.

It is very similar to New York Fern (formerly Thelypteris noveboracensis, now known as Amauropelta noveboracensis), which can tolerate a bit drier conditions and would make a good substitute. Keep in mind, though, that New York Fern can become a dominant understory species and may out-compete the seedlings of certain tree species. The seedlings of Wild Black Cherry (Prunus serotina) are especially vulnerable, as the fern releases an allelopathic phenol which can kill them.

New York Fern (*Amauropelta noveboracensis*) is a close lookalike to Marsh Fern and can be used is slightly drier settings.

Honorable Mention

Cinnamon Fern (Osmunda cinnamomea) – Cinnamon Fern has gorgeous fall colour, prefers part to full shade and will tolerate full sun if it is in standing water. It will grow in most soil types, including muck, and can get almost as tall as its cousin, the Royal Fern. This is a great pond or bog plant.

Cinnamon Fern (*Osmunda cinnamomea*) – Photo Credit: bobistraveling, CC BY 2.0 via Wikimedia Commons

I don’t include it in my top ten ferns simply because I have not had great success keeping it alive. I’m on my third attempt to grow Cinnamon Fern and I may have to move it to a wetter area than where I have it now. But it is quite gorgeous – especially in the fall.

Ferns for More Experienced Gardeners

The ferns in this section really aren’t for beginners. That’s because they are a little fussier on their growing conditions, and/or they are very aggressive spreaders. But if you have the space and/or the appropriate conditions and/or the experience and want to try something interesting, these are, in my opinion, some lovely ferns to add.

Hay Scented Fern (Sitobolium punctilobulum) – A beautiful fern for large areas, it is an aggressive spreader that gets 1-3’ tall and gives off a scent of crushed hay in late summer.. Prefers light shade and moist to mesic soils but will grow in a wide range of conditions.

Hay Scented Fern (*Sitobolium punctilobulum*) – Photo Credit: Nicholas A. Tonelli, CC BY 2.0 via Wikimedia Commons

Bracken Fern (Pteridium aquilinum) – Full to part sun, drought tolerant once established, this very aggressive spreader is not suitable for small spaces. However, it is so tough that I have read that it will actually thrive in the dry shade under sugar maples (but I haven’t tried it – yet). As I’ve seen it growing along roadsides in sandy soils, it might make a good plant for a Hell Strip (boulevard) garden. It gets up to 4’ tall.

Bracken Fern (*Pteridium aquilinum*) – Photo Credit: Zeynel Cebeci, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons

Hart’s Tongue Fern (Asplenium scolopendrium) – I’ve tried to grow this rare (it is classified as “vulnerable” in Ontario), very unusual looking fern twice, in two different locations, but couldn’t keep it alive past the first year. A friend, however, has it growing beautifully in his yard. It wants part to full shade in rich, moist but well drained soil.

Maidenhair Spleenwort (Asplenium trichomanes) – This extremely delicate looking fern grows in full to part shade in rich, moist, well drained soils, and rocky terrain. I’ve seen it growing in crevices in limestone alvars with virtually no soil at all. It is small, about 6” tall, and is evergreen.

Maidenhair Spleenwort (*Asplenium trichomes*) growing by my water feature

The Rain Garden – Part 2: Plant Choices

Posted on December 29, 2023December 30, 2023 by ridgetownrick

Last month’s article “It’s Raining, It’s Pouring, My Garden is Growing” discussed the how and why to build a rain garden. In this month’s article I will share some of my favourite plants that are well suited to rain gardens. These plants can handle both having their feet wet on occasion, sometimes for days on end, yet can also tolerate long periods of dry soil.

The following plants are listed in alphabetical order by scientific name. Plants with hyperlink are ones that have a complete description on the Plant of the Month pages of this website.

The Sunny (to partly sunny) Rain Garden

Perennials

Swamp Milkweed (Asclepias incarnata) – 3′ to 4’ tall, a monarch host plant and an excellent nectar source for butterflies and even hummingbirds. The juice of this wetland milkweed is less milky than that of other species. It tends to bloom twice in a growing season when in gardens. Rare occasional white specimens are found in the wild and these have led to cultivars such as “Ice Ballet.”

Monarch caterpillar on *Asclepias incarnata* (Swamp Milkwee)

Marsh Marigold (Caltha palustris) – up to 18″ tall, this is one of the first wetland flowers to bloom in spring. Seeds should be sown as soon as they’re ripe and cannot dry out before sowing. Seedlings do not flower until the third year following germination. Plants also reproduce easily by division in early spring as the plants are emerging.

A thriving patch of *Caltha palustris* (Marsh Marigold)

Boneset (Eupatorium perfoliatum) 3′ to 4′ tall, has very distinct, bold leaves with a crinkly texture and the pure white flowers bloom for a long time. Nectar or and pollen of the flowers attracts many kinds of insects and it is a host plant for several moth species. Seeds need light to germinate in the fall, and sow thickly as germination rates are typically low. Stratification for at least 30 days will increase germination percentages. Seeds will last up to 3 three years if stored in the fridge. Boneset can also be propagated by root division in the fall just as they go dormant, or in early spring just as the first shoots appear

The crinkly, opposite leaves of *Eupatorium perfoliatum* (Boneset) wrap around the stem.

Joe-Pye Weed (Eutrochium maculatum) 5′ to 7′ tall, the flowers have a light vanilla fragrance that becomes more intense when crushed. An important food source for butterflies, bumblebees, green metallic sweat bees, and skippers, it is also the host plant for several moth species, including the Ruby Tiger Moth.

*Eutrochium maculatum* (Joe Pye Weed) flowers are a pollinator magnet.

Bottle Gentian (Gentiana andrewsii) 1′ tall, it is especially valuable to bumble bees, just about the only insect with enough strength to force its way into the closed flower. Plant tends to lean at maturity, so plant among sturdier plants for support. If left undisturbed, plants in optimum growing conditions will naturalize over time into large clumps.

Bumblebees are the only pollinators strong enough to break into the closed blossoms of *Gentiania andreswii* (Bottle Gentian)

Water Avens (Geum rivale) 1’ to 2’ tall, the intricate, droopy flowers of Water Avens will add a touch of elegance to your garden and are best enjoyed up close. They provide a long bloom time and turn into ornamental, fluffy seed heads. Water Avens maintains a clumping form and looks its best when planted en masse. The fragrant flowers were once used to flavour ales, and the roots can be boiled to make a chocolate-like drink.

The purplish-brown flowers of *Geum rivale* (Water Avens) provide an interesting texture to the rain garden.

Spotted Jewelweed (Impatiens capensis) AKA “touch me not”, this plant will get up to 5’ or more in height and will eagerly self-seed and quickly cover moist areas with beauty and wildlife value. Hummingbirds and butterflies seek nectar, and several native bees (listed by the Xerces society as of special value to bumblebees) collect pollen (it is listed by the Xerces Society as of special value to bumblebees). The juice from Jewelweed stems contains a compound called lawsone, which has shown to have antihistamine and anti-inflammatory properties. It is said to relieve itching from Poison Ivy, mosquito bites, and Stinging Nettle and has also been used to treat athlete’s foot.

Impatiens capensis (Spotted Jewelweed or Touch-me-not) is a succulent looking plant whose exploding seedpods delight children of all ages.

Blue Flag Iris (Iris versicolor) At 2’ to 3’ tall, this is a personal favourite of mine. Seeds require at least 4 months of cold, moist stratification to germinate and will take 2 years till they produce flowers. To propagate vegetatively, the roots can be divided in early summer.

*Iris versicolor* (Blue Flag Iris) plants

Cardinal Flower (Lobelia cardinalis) 3′ to 4’ tall, this is a hummingbird magnet in the garden. Although relatively short lived (usually 2-3 years) it can carry on in your garden by dividing it or moving it every year or two. This plant is at its finest when growing with minimal competition in forested wetlands. Note that commercial garden centers often sell cultivars of this plant, that may or may not be as valuable to wildlife as the true species.

*Lobelia cardinalis* (Cardinal Flower) makes a bold statement in a moist garden.

Blue lobelia (Lobelia siphilitica) 2’ to 4’ tall, the nectar attracts butterflies and native bees and occasionally hummingbirds. Pinch back the plants to make them bushier. Blue Lobelia will produce offsets around the base that will generate their own roots. These can be removed with a sharp knife in the spring or fall, being careful to retain their roots, and transplanted. These small offsets are delicate, so care should be taken not to bury them under thick mulch.

*Lobelia siphilitica* (Blue Lobelia) ranges in colour from almost pink to dark blue, sometimes with a splash of white of the blossom.

Monkey Flower (Mimulus ringens) 1’ to 3’ tall, adds a wonderful, refined look to wet sites and will spread slowly by rhizomes to take on a bushy look once mature. Its snapdragon-like flowers have a long bloom time, which is great for bees and gardeners alike. The dried seed heads provide great textural interest over the winter months.

*Mimulus ringens* (Monkey Flower) is a long flowering perennial that tolerates a wide range of conditions.

Golden Grounsel (Packera aurea) 1′ to 2’ tall, it puts on a luminous and long-lasting display of golden- yellow flowers in the springtime. It is a robust, bold- textured groundcover that will spread by both rhizomes and seeds.

The bright yellow blossoms of *Packera aurea* (Golden Groundsel) start out as deep purple buds, and brighten the garden.

New England Aster (Symphyotrichum novae-angliae) 3′ to 5′, this is a host plant for Checkerspot and Crescent butterflies and others, and for several moth species. New England Aster has a tendency to become root-bound and will benefit from dividing the plant every 3 to 4 years. Pinching back the stems a few times before mid-July will help to make the plant bushier and eliminate the need for staking.

The pinks and blues of *Symphiotrichum novae-angliae* provide long lasting fall colour, and the seeds attract many small birds in the late fall.

Blue Vervain (Verbena hastata) up to 5′ tall, it puts on a majestic display of candelabra-shaped flower clusters in mid-summer, filling the garden with accents of violet-blue. It maintains a clumping habit and makes a great structural plant. The rigid stems and seed heads stand tall through the winter to provide excellent seasonal interest.

*Verbena hastata* (Blue Vervain) is one of the taller rain garden plants, but isn’t a bully in the garden.

Shrubs

Buttonbush (Cephalanthus occidentalis) 5’ to 10’ tall, this shrub produces a unique white round flower head that is highly attractive to bees and butterflies. It can be pruned back in the spring if necessary. The shrub requires full sun but may tolerate some shade. Otherwise, buttonbush is extremely resilient in all types of temperatures and conditions. It is important to note that the leaves of this plant are toxic to humans.

The round, button-like flowers of *Cephalanthus occidentalis* (Buttonbush) make a unique garden feature

Meadowsweet (Spiraea alba) 3′ to 6’ tall, larval host for Spring Azure butterflies. Blooming for 1 to months, the pollen and nectar attract a wide range of bees, bumblebees, moths and other pollinators. It takes well to pruning after flowers have finished blooming. It does spread by rhizomes and may work better in a larger rain garden.

Spring Azure butterfly nectaring on *Spiraea alba* (Meadowsweet) blossoms

The Shady Rain Garden

Perennials

Yellow Lady’s Slipper (Cypripedium parviflorum) 1’ to 2’ tall, propagating these showy yellow orchids from seed is complex. The seeds are extremely small and contain no endosperm (the energy reserves in most other seeds) and cannot survive without a symbiont soil fungus to absorb nutrients for it. Most commercially grown Lady’s Slippers are germinated in the lab in a special medium, or by tissue culture, can take a year or more to germinate, and up to a decade or more before they flower. This is why lady’s slipper orchids are so expensive. If someone is selling you a Cypripedium orchid at a bargain price, chances are it was wild harvested. In the garden, plants that have grown very large (with at least 30 shoots) should be divided to keep the plant healthy.

A healthy clump of *Cypripedium parviflorum* (Yellow Lady’s Slipper orchids) in my garden had slowly grown from the original 2 stems.

Virginia Waterleaf (Hydrophyllum virginianum) 1’ to 2’ tall, is a reliable ground cover that puts on a verdant display of leaves early in the spring. Delicate -looking flower clusters rise above the leaves in late spring to dot the landscape with pastel purple hues.

Wood Lily (Lilium philadelphicum) 2’ to 3’ (occasionally up to 4’) tall, the stunning flowers add fiery red/orange accents to the summer garden, while its whorled leaves add an interesting texture. It has a very elegant look overall and maintains a clumping habit. Pair it with plants of similar height as it does not like competition. It’s slow to establish but well worth the wait.

Cardinal Flower (Lobelia cardinalis) – see above

*Lobelia cardinalis* (Cardinal Flower) is a hummingbird magnet

Royal Fern (Osmunda spectabilis formerly O. regalis) 3’ to 6′, it is one of the largest ferns in non-tropical North America. Fronds typically turn yellow to brown in autumn. Spores are located in brown, tassel-like, fertile clusters at the tips of the fronds, thus giving rise to the additional common name of flowering fern for this plant.

*Osmunda spectabilis* (Royal Fern) is a majestic addition to the rain garden.

Golden groundsel (Packera aurea) – see above

*Packera aurea* (Golden Groundsel) brightens a shady garden

Marsh Fern (Thelypteris palustris) 1’ to 2’ tall, this fern spreads to form a lush green ground cover in moist soil. Although it does well in sunnier rain gardens, it also thrives in moderately dense shade in my gardens. The Marsh Fern often forms dense colonies of leaves, it provides good cover for the smaller kinds of wildlife.

*Thaliyperis palustris* (Marsh Fern) will slowly spread to make a ground cover that helps keep the roots of other plants cool.

Shrubs

Witch-hazel (Hamamelis virginiana) 8′ to 20′ tall, it prefers moist, acidic, organically rich soils and will tolerate heavy clay soils. One of the last shrubs to flower. the stem-hugging clusters of fragrant bright yellow flowers, each with four crinkly, ribbon-shaped petals, appear along the branches from October to December.

Hamamelis virginiana (Witch Hazel) flower are among the last sources of pollen for late season pollinators

Northern spicebush (Lindera benzoin) 4’ to 15′, this fragrant (spicy) host plant for the Spicebush Swallowtail butterfly produces beautiful, tiny yellow flowers in the spring and makes a great alternative to the non-native Forsythia. Shrubs are either male or female, and if you’re lucky enough to get a female, you are apt to get bright red, spicy smelling fruit in late summer. In the fall, the leaves are brilliant yellow.

*Lindera benzoin* (Northern Spicebush) flowers

Brilliant yellows of Northern Spicebush in the fall.

It’s Raining, It’s Pouring, My Garden is Growing

Posted on December 1, 2023December 1, 2023 by ridgetownrick

Designing a Rain Garden

Most yards, whether urban or rural, are high and dry – and for good reason. No one wants to walk around on a sloppy, muddy lawn each time it rains.

During a heavy downpour, lawns can sometimes get pretty soggy.

However, such lawns limit the species we can grow to those that don’t require a lot of water, and we have many beautiful native plants that actually appreciate having their “feet wet”, at least occasionally. At the same time, our rooftops collect gallons of water every time it rains, and often the water is diverted to sewers or ditches, or simply directed onto the lawn. A solution to both these problems is the rain garden.

What is a Rain Garden

In its most basic form, a rain garden is a depression in the lawn where water from downspouts is directed each time it rains and in which we plant some water-loving plants. But to be truly effective, the garden needs to be designed to match your soil type and the amount of rain collected from the roof, otherwise you could end up with a mud patch that never dries, or a garden that gets a flush of rain once in a while but soon dries up. And although there are plants that will survive either of these scenarios, a properly designed rain garden will offer a long term, beautiful garden solution.

This month’s article is on how to design and build such a rain garden.

Some lovely newly established rain gardens at the home of Jo-Anne Smith in Leamington, Ontario. These well designed gardens are effectively trapping rainfall and allowing it to soak into the soil rather than run into the storm sewer. In a couple of years (or less) these will be full of lush native plants. (Photos courtesy of J. Smith.)

The Four Main Considerations – Water, Soil, Calculating the Area, and Plants

Part 1 – How Much Water Do I Have?

Calculating how much water you can collect from your roof is actually pretty straightforward (more so when using metric measurements – but I’ll give the formulae for both). A good rain gauge and some long term records are best for accuracy, but you may be able to get enough information from the weather reports. But designing your garden properly requires knowing how much rain you’re apt to get in the growing season, and for this you need historical records.

In Canada, you can look up historical normal rainfall through Environment Canada’s Website at https://climate.weather.gc.ca/climate_normals/station_select_1981_2010_e.html?searchType=stnProv&lstProvince=ON and simply select your city (or a nearby city, if it doesn’t have data for your town).

In the USA, try https://www.currentresults.com/Weather/US/average-annual-precipitation-by-city.php

Once you’ve found what your normal rainfall amounts are (by month is ideal), then you need to know how much of that rainfall your roof is collecting. (If you know of a source of the historical maximum rainfall amounts in various locations across the country, please let me know.)

Calculating Potential Rain Capture

Calculating the amount of rain your roof captures is the easy part (sort of). A simple method is to measure the dimensions of your house, then divide it into sections that are captured at each downspout.

Blue indicates section of roof feeding a single downspout.

For instance, my house is a small wartime bungalow, approximately 9.2 m X 8.6 m or (very roughly) about 80m² of roof area (about 30’ X 28’ = 840 sq ft). There are two downspouts, one on each side, each collecting from 40m² (420 sq ft) of surface area. (We’re not interested in the actual surface area, but instead just the area that intercepts rainfall.) If you don’t know the dimensions of your house, you can use Google maps (satellite view) to measure the area.

Metric and Imperial dimensions of my house, indicating approximate area collecting rainfall at each downspout.

If you’re using metric measurements, it’s simply the area in square meters multiplied by the rainfall amount in mm. This gives you the volume of rainfall in litres.

If you’re still using imperial measurements, the formula is roof area in sq ft x the rainfall in inches x 0.623m, which provides you with the total (US) gallons of water (to convert to imperial gallons, multiply by 0.83).

In the example of my house, a 25 mm (1”) rainfall event will collect:

25 mm X 40 m² = 1000 L of water (or 1” X 420 sq ft X 0.623 = 261.7 US gal)

(to convert to imperial gallons: 261.7 US gal X 0.83 = 217.2 Imp gal)

Part 2 – Determine Your Soil Type

You’ll also need to have an idea of your soil type. Clay soils will need a larger garden than sandy soils because clay does not drain as readily (we’re not building a pond – we actually want the water to soak in and drain away through the soil so that it doesn’t become a mosquito hatchery). There is an excellent article on how to determine your soil type at https://www.rhs.org.uk/soil-composts-mulches/soil-types. Another, slightly more detailed and technical article, can be found at https://www.gardeners.com/how-to/what-type-of-soil-do-you-have/9120.html.

Once you know your soil type we can put all this information together to calculate the size of your rain garden.

Building the Right Size Rain Garden in the Right Place

If your garden is too small for the amount of rain you are apt to get, it will overflow into the lawn. If it’s too big, your plants may not get enough moisture.

Also, your rain garden should be at least 3 m (10’) from the foundation. If it’s too close to the house, you could end up with a wet basement.

Large rain gardens will take more time to maintain and money to complete but will be more effective for capturing runoff. However, relatively small rain gardens can still capture stormwater and improve water quality.

Part 3 – Calculating Area

Typically, residential rain gardens are between 10 to 30 square metres (100 to 300 square feet) and 10 to 20 centimetres (4 to 8 inches) deep. However, to maximize the efficiency of rainwater use, the surface area of your garden should be about 20% (for sandy soil) up to 45% (for clay soil) of the cumulative drainage area (that area of the roof feeding the downspout going to your rain garden). Note that these percentages are simply a guideline – in fact many sources indicate widely different values – anywhere from 10-20% (sand to clay) all the way to 20-65% (sandy to clayey). These percentages are referred to as the “Soil Factor”.

Therefore, in my example above, if I am collecting rain from just one downspout and using my suggested Soil Factors, my rain garden should ideally be:

Sandy soil: 40 m² X 0.20 = 8 m² (420 sq ft X 0.20 = 84 sq ft).

Loam soil: 40 m² X 0.30 = 12 m² (420 sq ft X 0.30 = 126 sq ft).

Heavy clay soil: 40 m² X 0.45 = 18 m² (420 sq ft X 0.45 = 189 sq ft).

And if your rain garden is more than 10 m (30’) from your downspout, you will need to factor in the surface area of lawn and driveway, etc. that are also feeding into the garden.

What if My Lawn has a Slope?

It is important to keep the garden level for optimal filtration so if your lawn is sloped, you may need to do some “cut and fill” (removing soil at the high end and spreading it to the lower end – possibly adding a berm to retain water).

The slope of your lawn should determine the depth of your rain garden and the slope can be determined by following these steps:

Place one stake at the uphill end of the rain garden site and place the other stake at the downhill end. The stakes should be approximately 4.5 metres (15 feet) apart.

Tie a string to the bottom of the uphill stake and run it to the downhill stake.

Using a carpenter’s level, make the string horizontal and tie it to the downhill stake at that height.

Measure the width between the two stakes.

Measure the height on the downhill stake from the ground to the string.

To find the lawn’s percent slope, divide the height by the width and multiply the result by 100.

How Deep Should the Garden Depression Be?

• If the slope is less than 4%, build a rain garden that is approximately 7 to 14 centimetres (3-6 inches) deep.

• If the slope is 5-7%, build a rain garden that is approximately 15 to 18 centimetres (6-7 inches) deep.

• If the slope is 8-12%, build a rain garden that is approximately 20 centimetres (8 inches) deep.

Laying Out the Rain Garden

Finally, you must determine the design of your rain garden. To do this, simply choose a garden width that best suits your property and landscaping. Next, divide the surface area of your garden by the garden width to determine the garden’s length. As for shape, crescent, kidney and teardrop shaped gardens can be quite attractive.

If your proposed garden isn’t a simple rectangle, and you’re not sure how to determine the area, there’s an excellent tutorial at https://www.hollandbulbfarms.com/garden-area-calculator and a more technical approach at https://www.youtube.com/watch?v=Rogg7stSj6c .

Getting Water Into and Out of the Garden

Finally, some consideration about the inlet and outlet to your rain garden. If your downspout empties directly into the garden, you’re set at that end. If you don’t want the downspout running across your lawn, you may decide to make a dry streambed of river stone between the downspout and garden for an added feature, bury some Big-O pipe in the lawn, or simply create a grassed shallow channel. In this last case, it can be helpful to add a few stones at the garden entry area to slow the water flow for days of heavy rain to prevent erosion.

In periods of torrential rain, the rain garden may overflow. If your lawn is sloped, you’ll want to create a low, stone-reinforced exit so that the berm doesn’t get washed away.

A Note of Caution on Mulching Your Rain Garden

Many of us like to use wood chips or other mulch on our flowerbeds. Keep in mind that after a heavy downpour, wood chips and many other mulches will likely float to the top and may overflow onto your lawn. If you need to use a mulch, consider stone or other heavy substance.

Next Month – Part 4 – Plants for a Rain Garden