Building a Mini-wetland

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.

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.

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.

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.

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.

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.

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)

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? 

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: 

  1. It is introduced to an ecosystem outside of its native range, and 
  1. 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. 

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).  

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. 

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. 

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) 

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 

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 

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.  

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.   

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.   

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.  

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. 

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.  

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.  

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). 

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. 

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). 

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.  

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. 

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. 

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. 

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. 

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.  

The Rain Garden – Part 2: Plant Choices 

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.” 

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. 

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 

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. 

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. 

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.  

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. 

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. 

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. 

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. 

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. 

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. 

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. 

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. 

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. 

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. 

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. 

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 

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. 

Golden groundsel (Packera aurea) – see above 

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.  

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. 

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.  

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

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. 

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.

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”. 

Soil Factor table.

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: 

  1. 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. 
  1. Tie a string to the bottom of the uphill stake and run it to the downhill stake. 
  1. Using a carpenter’s level, make the string horizontal and tie it to the downhill stake at that height. 
  1. Measure the width between the two stakes. 
  1. Measure the height on the downhill stake from the ground to the string. 
  1. 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 

Can I Eat My Garden? 

There are entire books on edible wild plants and on foraging, but I’ve never really paid much attention to them (even though I do have a few on my bookshelves).  For me, growing native plants is all about feeding Mother Nature, not about feeding me. But this year I harvested the first of my native wild black currants (Ribes americanum) with the hopes of possibly making a small batch of jam. So I thought for today’s article I would share with you some of the edible plants that grow in my garden and how I have used them. I’ve been told there are lots more that are edible in my garden than what I discuss here, but I’ve never tried tasting them. (Perhaps in the future I may do a series of articles on edible native plants that you can grow. But that will take a lot more research than I have time to do at the moment.) 

Wild Black Currant – Ribes americanum 

I planted two Wild Black Currant shrubs a couple of years ago. Last year they had a few currants, but this year they were loaded with fruit. Interestingly, the currants do not ripen all at the same time like the non-native red currants I have. Instead, one or two currants in each cluster will start to ripen, eventually becoming ripe enough to pick (if you get them before they fall off) and there will still be tiny green fruits on each cluster along with currants at various stages of ripeness. This makes harvesting a slow and tedious process. I collected fruit as it ripened over a period of a couple of weeks and put them in the freezer to make into jam once I had enough. That will be a winter project. 

Wild Black Currants don’t taste quite the same as their European cousins – I find them to be a tad more bitter, but any black currant jam recipe will work – though you may want to add a little more sugar.  

Wild Black currants will do well in any moist, well-drained soil (even heavy clay) and tolerate part shade to full sun. They get up to 6 feet tall and so far the plants in my garden don’t seem to be suckering, but if a stem touches down on the soil it may root. (Because of this, starting new plants from cuttings is very easy).  

Wild Ginger – Asarum canadense 

An early spring blooming plant of the forest floor, in my opinion Wild Ginger only superficially tastes like store bought ginger – the flavours are a bit more complex (one author described it as more peppery). You can grind it or slice it and use it in traditional recipes in place of commercial ginger but use with caution. This plant contains Aristolochic Acid (AA) which, in large doses, can be fatal – do your research before cooking with it. It does, however, make a good tea when steeped (AA is barely soluble in water so you would be unlikely to get enough to harm you). 

Wild Ginger wants full to part shade in moist rich soils. It will tolerate drier soils once established and is a great ground cover under those shady maple trees. 

Jerusalem Artichoke – Helianthus tuberosus 

The tubers from this sunflower relative get to about the size of fingerling potatoes (or even fist sized in some varieties) and can be cooked any way you cook potatoes. My personal favourite is to roast them in the oven with a bit of olive oil, salt and pepper. (As with oven roasted sweet potatoes, this seems to intensify the flavour). The center will go mushy when it’s cooked this way, but they are quite delicious. I’ve tried them pan-fried and boiled, too, but I always go back to oven roasting.  

Be forewarned, though – the tubers contain a lot of the soluble fibre inulin which can cause gas and bloating in some people (hence one of the plant’s common names – fartichoke). 

Jerusalem Artichoke will grow well (some say too well – it is a fairly aggressive spreader) in loose, well drained soils in full sun to part shade. But it’s not all that fussy about soils – a friend grows it very successfully in her garden which is heavy clay. It does like the soil to be a bit on the moist side for larger tubers, but it will rot if the soil is too wet. 

Wild Black Raspberry – Rubus occidentalis 

There are few treats sweeter than finding a Wild Black Raspberry bush full of ripe berries along the edge of a forest in early to mid-summer. Though they tend to be a little “seedier” than their red commercial cousins, they pack a lot of punch into a thimble-sized fruit. I like to eat them fresh, on their own or mixed with other berries, and drizzled with cream, or with a dollop of ice cream. But they also make an awesome jam, upside-down cake, crumble or any other sweet treat that you can use red raspberries for. And they freeze well. 

Wild Black Raspberries grow on canes that can reach up to 9’ long or more in full sun to part shade and they prefer moist, rich loamy soil, but will do well in a wide range of soil and moisture regimes. Wherever the tip of a cane touches down, it will root and send up a new stem. These new canes often have a bluish colour, allowing you to readily differentiate them from other raspberries and blackberries.  

Wild Leeks – Allium tricoccum 

Ramps, Leeks, no matter what they’re called, people will go to great lengths to collect these for the table each spring. Unfortunately, unscrupulous foragers have decimated wild populations throughout our region. Use Leeks where you would use their non-native, commercial cousins in your cooking.  They have a sort of garlic-shallot-cross flavour that can be quite intense. (As a young person, I planted trees and traveled to the planting sites in a van of Wild Leek eating co-workers, and the fumes were so powerful I’d sit with my face to the open window – despite the barely above freezing temperatures.)  

Leeks need rich, loose loamy soil with lots of organic matter and full to part shade. The leaves appear in spring for about a month to 6 weeks then disappear till the following spring. But if you’re observant, by mid- to late-summer, you’ll see a stem appear with white flowers that turn to tiny black seeds by early autumn. 

Virginia Mountain Mint – Physostegia virginiana 

I have only ever used Mountain Mint in tea, but its minty leaves and flower buds can be added to salads or used as a condiment (I’m thinking it would be fabulous on lamb chops). The leaves can be dried or used fresh.  

This hardy perennial is happy in most garden soils, from sandy to clay, and full sun to part shade, though it likes soils that aren’t too dry.  

Anise Hyssop – Agastache foeniculum 

Anise Hyssop, though not actually native to the southern Great Lakes region, is a pollinator magnet so I keep it in my garden. The licorice (anise) flavoured leaves and flowers, either fresh or dried, can be steeped to make a lovely tea. And though I haven’t tried it (yet) I recently found a website that said it can be added to hot chocolate, or blended into smoothies or cocktails. 

This short-lived perennial likes dry to medium, well drained sandy soils in full sun to part shade. In my garden, it is always covered with various bees when it’s in flower and the flowers last for several weeks. 

American Spikenard – Aralia racemosa 

The large clusters of burgundy berries on American Spikenard have a mildly sweet, almost floral flavour about them and are said to make excellent jams, jellies or fruit leather. I have only eaten them fresh but have a container-full in the freezer awaiting a slow-down in the garden so I can make them into jam.  

This perennial likes part shade (it is a forest edge species) that grows fast – it can get up to 150 cm (5’) tall in a single growing season before it dies off for the winter. The white flowers appear in early summer and the fruit starts to ripen in mid- to late-August. It prefers wet to medium-moist, fertile, humus rich soils.  

Wild Strawberry – Fragaria virginiana/Fragaria vesca 

As a kid, I loved finding a patch of wild strawberries in the fields at my uncle’s farm. The tiny red fruit packed all the flavour, and more, of the store bought counterparts. A bowl full of wild strawberries with cream was an amazing treat. They also make a great jam, and I have thrown fresh berries in a salad (when I’ve had lots). The challenge in my garden is beating the squirrels and birds to the ripe fruit. 

F. variegata (Wild Strawberry) differs from F. Vesca (Woodland Strawberry) in that the former likes full sun while the latter prefers full to part shade. The berries and leaves look very similar to the untrained eye, but there are subtle differences. Both species grow best in moist to medium moisture regimes (though Woodland Strawberries prefer the wetter end of the spectrum and Wild Strawberries the drier end), and neither is fussy about soil texture (sand, loam, clay). 

Happy (and tasty) Native Plant Gardening. 

Got Shade Part 3 – Late Season Shade 

Fall tends to be a quiet time for flowers in the forests. Long gone are many of the showier shade perennials like Woodland Poppy (Stylophorum diphyllum) and the Meadowrues (Thalictrum species). And the spring ephemerals like Trilliums and Jack-in-the-Pulpit (Arisaema triphyllum) are a distant memory. But it doesn’t mean the shade garden has to be bleak. There are some lovely shade plants that come to life this time of year – either with late season blooms, colourful berries or lovely fall foliage. Here are a few that can make your shade garden look nice as autumn rolls around. 

Forest floor in autumn

Fall Flowers 

Let’s start with fall flowers. In my gardens, Asters are the fall showstoppers. Whites, blues, purples and pinks abound. Mix in the yellows of goldenrods (Solidago spp) and Woodland Sunflowers (Helianthus divericatus) – at least into September – and you’ve got a winner. If your shade is moist, you may even have Cardinal Flower (Lobelia cardinalis), Blue Lobelia (L. siphilitica) or Sweet Joe Pye Weed (Eutrochium purpureum) lasting well into September.   

But the true Autumn flowers for shade are the whites of White Wood Aster (Eurybia divaricata), Schreber’s Aster (E. schreberi) and Large-leaf Aster (E. macrophylla), and the blues of Blue Wood Aster – aka Heartleaf Aster – (Symphyotrichum cordifolium), Lowrie’s Aster (S. lowrieanum) and Short’s Aster (S. shortii).

If you have light or partial shade, you can add the pinks and purples of New England Aster (Symphyotrichum novae-angliae), the blues of Sky Blue Aster (S. oolentangiense) or the whites of Arrow-leaved Aster (S. urophyllum) or Flat-topped White Aster (Doellingeria umbellata). Even the purple Swamp Aster (Symphyotrichum puniceum) can handle part shade if the soil is moist enough.  

For a splash of yellow, consider Zigzag Goldenrod (Solidago flexicaulis) or even Green-headed Coneflower (Rudbeckia laciniata). And Bluestem Goldenrod (Solidago caesia) will give you lovely sprays of yellow well into September as well. 

White Snakeroot (Ageratina altissima) starts flowering with its umbels of white in midsummer and is going to seed by early September, but I find that it often sends out a second flush of flowers (even while the seeds are forming) that can last to the end of September and some years into early October. 

And if your shade garden has room for some shrubs, the frilly yellow flowers of Witch Hazel (Hamamelis virginiana) appear in October to November here in southwestern Ontario. 

Leaves and Berries 

Flowers aren’t the only things to provide autumn colour in the shade garden, though. Several fruiting shrubs and vines also provide colourful seeds and berries, or golds and purples of fall leaves. One such shrub is Northern Spicebush (Lindera benzoin) with its candy-apple red berries and bright yellow leaves in the fall. Another shade tolerant shrub with red berries that is loved by the birds is Red Elderberry (Sambucus racemosa) though, unlike the common elderberry (Sambucus canadensis), the berries are not edible for humans. In the southern Great Lakes region, the fruit of Red Elderbery can often be found on the plants (providing the birds don’t find them first) well into November.  

If you want a woody perennial, but don’t have room for a tall, spreading shrub, a ground hugging forest shrub (or short vine) with intriguing fruit is Running Strawberry Bush (Euonymus obovatus). Its rough pink seed pods open to display bright orange berries. But if you plant these, know that (in my garden, at least) the rabbits eat it back to stubs just about every winter. 

A long lasting understory plant is False Solomon’s Seal (Maianthemum racemosum) that produces plumes of beautiful white flowers in the spring that become clusters of Vitamin-C rich edible red berries in the fall.

Another medium-short forest shrub with blue-black berries in September and pink to purple leaves in October is Maple-leaf Viburnum (Viburnum acerifolium). This dainty beauty prefers moist shade.  

And ferns are always a good structural plant for shade gardens all season long. These plants provide filler when the spring ephemerals disappear and keep your garden looking lush well into the fall. There are so many to choose from, though some of my favourites are Lady Fern (Athyrium filix-femina), Christmas Fern (Polystichum acrostichoides), Sensitive Fern (Onoclea sensibilis), Ostrich Fern (Matteuccia struthiopteris) and Bulblet Fern (Cystopteris bulbifera) as these particular ferns look great in a wide range of soil types and moisture regimes. Perhaps I will put together an article on ferns in the not too distant future. 

Happy Native Plant Gardening – in the Shade.

Fall Garden Prep for the Native Plant Garden 

The leaves are starting to turn colour, the air is getting cooler, and there are lots of gardening articles being written about what to do with your Canna Lilies and rose bushes and dahlias for the winter. But what about those of us who grow native plants? Do we have to do anything to prepare our plants and flower beds for winter? After all, Mother Nature has been looking after herself for millennia. 

How much fall prep you do will depend primarily on WHY you grow native plants.  

Leave the Plant Stalks 

When I started growing natives, I came from a background of conventional gardening, and the easiest way to put my native plant gardens to bed for the winter was to simply set my mulching mower as high as it would go and mow everything down. The result was a tidy looking flower bed that was ready to emerge in the spring.  

In the spring, after an extensive fall clean up, the flowerbeds looked tidy, but there was no shelter for overwintering insects.

Unfortunately, I also removed important habitat for bees and other insects. 

As my understanding grew of the importance of leaving stems for leaf cutter and wool carder bees and for small carpenter bees and others, I had to change my mind set. I started to leave a few of the pithy stems of Monarda (Bee Balm and Wild Bergamot) but I still “cleaned up” the rest of the flower beds by cutting down the asters, Joe Pye weed, coneflowers, etc. and hauling the debris to the municipal yard for composting.  

Leaving those stems was really hard to do – at first. It offended my sensibilities as to what a neat and tidy garden should look like for the winter. But whether it was my imagination or reality, I thought I detected more bees the next year, and more species of bees as well. So when fall rolled around again I compromised – I cut down most of the plants to about 18”, and rather than hauling the debris away, I cut it into 1-2’ lengths and left it on the ground.

Because my gardens are very densely planted, and some with very tall plants, I would have had a foot of cuttings if I dropped them all in the garden, so I kept it to a minimum by leaving one thin layer in the flowerbed, and placing the remaining stems in an out of the way corner of the yard. 

Surprisingly, it was my mindset that had the greatest change as a result of this new strategy. I no longer saw a “mess” in the flowerbed in the fall. Instead, I saw potential habitat. I saw that I was giving Mother Nature a helping hand. It’s one thing to provide native plants for bees, butterflies and caterpillars to feed on during the summer, but if you don’t provide them with a place to overwinter, then you are really only helping those species that migrate. 

Leaving the flower stalks has, in addition to the wildlife benefit, the added beauty of great structure in the winter garden. 

But is leaving the stems the only thing we can do?  

Leave the Leaves 

Leaving the leaves on our lawns is just about as difficult to do as leaving plant stems in the gardens for the winter for most of us. But it is just as important. I do rake my lawn in the fall, but I have much less area of lawn than I do of flowerbeds, so the leaves get raked onto the beds. They provide mulch to keep annual weeds down in the spring, and fertilizer as the leaves decay. And depending on the bed, I may put just a thin layer (on the beds of prairie species, for example) or a layer at least 6” thick under the sugar maples where Trilliums, Jack in the Pulpit, and other spring ephemerals need the organic matter and moisture retaining quality of the decaying leaves.  

Most of our spring forest wildflowers require deep, humus-rich soils to flourish. Decaying leaves provide this.

I actually have so many trees in my yard now that I now create piles of the excess leaves in the fall to be spread over the shade garden in mid-May when most of the leaves there have been consumed by insects, worms and microbes.  

But why is it important to leave the leaves, other than for mulch and natural fertilizer? 

For starters, many of our butterflies and some of our more spectacular moths overwinter in the leafy debris. 

According to the Royal Ontario Museum’s book Butterflies of Ontario, of the 127 species of butterflies in this province, 110 overwinter here.  

  • 6 overwinter as adults 
  • 12 overwinter as eggs 
  • 30 overwinter as a chrysalis 
  • 60 overwinter as a caterpillar, and  
  • 2 overwinter as either a caterpillar or a chrysalis. 

Many of these hide either in the leaf litter or in the ground (where the leaf litter helps to keep them warm). 

Many of our moths do the same. The ones we tend to get excited about – the large, showy ones – are no different. For instance, the beautiful green Luna Moth overwinters by using its silk to bind dead leaves around its cocoon. The Virgin Tiger Moth overwinters as a caterpillar, hiding in the leaf litter. And as for everyone’s favourite – the Hummingbird Clearwing Moth – the fully-grown caterpillars burrow in the leaf litter to pupate, emerging soon after and overwintering as an adult, or waiting in the cocoon until the following spring to emerge.  

So the less we can disturb the leaf litter, the better, as far as I am concerned.  

Do it for the Bees, Too 

We also have a number of ground nesting bees that greatly benefit from a quilt of leaves to help maintain a comfortable temperature all winter long. The leaves have the added benefit of slowing down the heating of the soil in a January thaw that might cause the bees to emerge too early before any food sources are available. 

The American Sand Wasp (Bembix americana) is just one of many ground nesting bees and wasps. These wasps are solitary predators that primarily target flies – including the annoying horse and deer flies – for their developing larvae. When the larvae mature, the tunnel is sealed for the winter. They pupate in spring and come out from their tunnels in summer.

As you start thinking about preparing your garden for its long winter rest, think of the insects that need the stems and leaves to survive till spring. Leave some stems, and leave the leaves. 

Got Shade? Part 2 – Summer in the Shade 

This spring, I wrote an article about spring ephemerals – those woodland species that flower early in the spring and then, for the most part, disappear till the following year. Summer has arrived and we have a number of shade tolerant plants for your woodland gardens that bloom through the summer and into the fall. In today’s article, I’ll talk about some of these and share some images from my shadier gardens. 

Plants that grow under the tree canopy of a forest have to be tough. Not only do they need to compete with tree roots for moisture, they need to be able to collect light that filters through often dense canopies of leaves. Many of these plants collect as much energy from the sun as possible before the trees leaf out, then “coast” on that stored energy for the rest of the summer. But a few plants buck the trend and manage to grow, produce flowers and set seed under shady conditions that few others could tolerate.   

One thing I have observed that almost all these plants have in common is large leaves. They require maximum leaf area to absorb the few photons of light that filter through the trees, with their leaves designed to work at maximum efficiency. (Compare, for instance, the leaf of shade tolerant Asclepias exaltata – Poke Milkweed – to those of the sunny, open prairie species Asclepias verticillata – Whorled Milkweed or of the shade tolerant Lobelia inflata – Indian Tobacco – with the sun-loving Lobelia spicata – Pale Spiked Lobelia). 

Another thing I have noticed these plants tend to have in common is that their flowers are mostly white, green, pale blue or pale yellow (at least until the fall, when a few brighter colours – mostly yellows – appear). Whether this has to do with the plants requiring more energy to produce colourful flowers (speculation on my part) or because in shady areas these colours show up more for the pollinators to find, I have no idea. Two exceptions are the brilliant reds of Monarda didyma (Beebalm) – not normally associated with shade gardens, but it thrives in moist dappled shade in my garden – and Lobelia cardinalis (Cardinal Flower). 

It is the end of July as I write this, and a few late-spring/early-summer shade tolerant plants have now finished blooming and are setting seed. These include Thalictrum pubescens (Tall Meadowrue), T. dasycarpum (Purple Meadowrue), T. revolutum (Waxy Meadowrue) and Asclepias exaltata (Poke Milkweed). 

Monarda didyma (Beebalm) and Lobelia cardinalis (Cardinal Flower) are both in full flower right now in full light shade where they brighten dark corners with a brilliant flash of colour, and attract hummingbirds and butterflies. And new to my shade garden this year, but doing nicely, is the porcelain blue Campanulastrum americanum (American Bellflower). Lobelia inflata (Indian Tobacco, aka Puke Weed) is also flowering now in full (but relatively light), moist shade with delicate, pale bluish flowers. 

Just starting to bloom in my shade gardens are Eurybia macrophylla (Large-leaf Aster), Eurybia schreberi (Schreber’s Aster), Aralia racemosa (American Spikenard), Ageratina altissima (White Snakeroot), Actaea racemosa (Black Cohosh), Scrophularia marilandica (Late Figwort) and Circaea lutetiana (Enchanter’s Nightshade). These are joined by a large patch of Impatiens pallida (Yellow Jewelweed). Even some Veronicastrum virginicum (Culver’s Root), another plant like Beebalm that isn’t normally thought of as a shade tolerant plant, is doing great under the dappled shade of Gymnocladus dioicus (Kentucky Coffeetree). 

We also have some lovely plants suitable for part shade. These would normally be found at the edges of forests, and can tolerate quite a bit of shade. However, many of them tend to flower more prolifically with the benefit of more sunlight. Most books suggest that Solidago juncea (Early Goldenrod) requires full sun, but it is doing well under a large sugar maple in my yard where it gets only a half hour or so of direct, late afternoon sun. As its common name suggests, it is one of the earliest goldenrods to flower and starts flowering in my southwestern Ontario garden around the third week of July.  

A number of other shade plants – mostly asters and goldenrods, but also some interesting woodland species – will start to bloom in the next few weeks but I’ll leave those for a later article. We also have lots of shade-loving ferns, grasses and sedges, and a few great shrubs for shade, but those, too, will have to wait. 

Note that none of the plants listed above will thrive in deep shade such as that often found under Norway Maple, evergreens (like spruce or cedar) or close to the north side of a building, but they will all do very well in dappled shade (from less dense canopies such as under Kentucky Coffeetree) or if planted near the edge of the shade where they can get sun for at least part of the day.  If you do have deep shade, you may want to consider some of our spring ephemerals mixed with ferns, for now. 

Happy native plant gardening.