Boulevard Gardens

A Note on Boulevard Gardens 

Most suburban, and some urban, yards have a narrow grass strip between the sidewalk and the street. Invariably the municipality requires you to maintain this strip despite it being their property. And because it is their property, they often have restrictions as to what you can or can’t do with it (always check with your municipality before creating a boulevard garden). Some of these restrictions make total sense – like the ones that say don’t plant tall things that will block driver and pedestrian visibility, don’t plant tall shrubs or trees that may interfere with overhead wires, or don’t place large boulders that could interfere with maintenance (including snow removal) equipment. In addition, because it is municipal property, municipal work crews have a legal right to access it any time for maintenance of overhead or underground infrastructure, or when repairs to sidewalks, curbs and streets are necessary. As a result, your nicely tended flower bed could be unavoidably trampled. 

A couple of blocks from me, someone planted a tiny blue spruce in the median a few years ago. It is directly under the power lines, and pretty soon the branches will be blocking the sidewalk and extending into the street. I can’t imagine the municipality will be letting it go much longer. I’m surprised it has stayed this long.

So, what CAN you do with this area – an area that I have often seen referred to as a “hell strip”. These strips get this reputation because they are often comprised of compacted fill from when the street and/or sidewalk was put in. They get salt deposited when snowplows push snow onto them. Melting snow and contaminated street water get splashed onto them when cars drive by. And they’re very handy spots for pets to “do their business” when being walked. It’s a wonder anything grows there at all. 

However, if properly planned, these otherwise boring grass strips can provide year-round natural beauty, excellent pollinator habitat, an opportunity to educate your neighbours, and can even reduce maintenance – no weekly lawn cutting is necessary.  

But you need to choose your plants wisely. Boulevards require plants that not only tolerate the shade/sun/moisture conditions that may be present, but also a certain amount of salt accumulation, dog urine and even some trampling by pets and neighbourhood kids, all while meeting stringent height restrictions. These plants have to be extra tough. But we have lots of native plants to choose from (a very abbreviated list at the end of this article provides just a few examples). 

Creating the Boulevard Garden 

Call before you dig. Often utilities are buried in, or very near to, boulevards. Telephone (now usually used for your internet) and cable lines, in particular, are often buried in very shallow trenches – more often than not by simply inserting a spade into the ground and dropping the line in. Pushing your shovel into the ground can easily sever these wires (I speak from experience!).  

Some municipalities require you to apply for a permit and there may or may not be a cost associated with this. Depending on where you live, the municipality has the right to rip out unauthorized plantings on their property and even bill you for the labour involved. So check very carefully – you can usually find the information on the municipality’s website. 

Once you get permission and know your municipality’s rules on boulevard gardens, and your utilities have been located, you can start to plan the garden.  

What do You Have to Work With? 

Let there be light! 

First of all, determine the general conditions of your hell strip. Is it full shade, part shade or full sun? One way to figure this out is put a couple of stakes in the ground where you want to plant, then check it mid-morning, noon, and late afternoon so see how much light the plants will get. This will greatly narrow the selection process for picking your plants. Although it is not a hard and fast rule, most sources will say that anything greater than 6 hours of direct sun is considered full sun. Part sun (or part shade) is usually considered as 4-6 hours of sun. Full shade does not mean NO sun as most plants require some sunlight, even if it is diffused or dappled. Full shade usually means 4 hours of sunlight or less. 

All the Dirt 

Is the underlying soil clay, sandy, or construction rubble? This will likely depend on a LOT of things – how old your neighbourhood is, how recently the streets and sidewalks had a major repair (such as sewers being dug up), and what the parent soils are.  

It might take a bit of research, but you can find out your soil type by Googling ‘Soil Maps’ and your province/state (sometimes even municipalities will be able to provide this info).   

You can also dig a hole and do a percolation test – these are regularly done for septic beds to determine the size of bed needed – and use the results to determine soil type. To do the perc test, dig a hole 15 to 30cm deep, fill the hole with water a few times and let it drain out to saturate the soil (this could take a several hours – especially if you have heavy clay). Put a ruler in the hole that extends to the top and fill the hole with water again and monitor how long it takes for the hole to empty (be patient, this is a slow process). 

If the water infiltrates 20-30 mm/hr, the soil is sandy loam. If it only goes down 10-20 mm/hr, you have loam soil, 5-10 mm/hr is clay loam, and if the water only drops 1 mm/hr then you know you have clay soil. (I did say it was a slow process.) 

Another way to determine soil type is by doing a ribbon test. A soil expert can do this with confidence, but I always find the ribbon test to be quite subjective. There are great videos online on how to do a soil ribbon test and how to interpret it if you want to try that. 

My boulevard is extremely wide, which gives me a lot of planting room. (I took this photo many years ago, before I discovered native plant gardening – all the non-natives in this boulevard garden are now long gone!)

Wet or Dry? 

Are you on the top of a hill where all the water will run away? Are you at the bottom where it will collect? I’m at the top of a knoll and have a very wide boulevard, but it was contoured as a shallow ditch to take water away. Unfortunately (or maybe fortunately) my neighbour’s drive is raised enough that in very heavy downpours water can accumulate. In my case it doesn’t last long as I have very sandy soil, but if this was clay soil, I’d have a mini lake every time it rained and would need to find plants that could stand having their feet wet for extended periods. If you are on sandy soil, with full sun, you are going to be limited to prairie species that can tolerate drought. If your boulevard is well shaded, especially if you have heavy clay soil as well, you won’t be able to grow typical prairie plants at all. 

What Grows Well in a Hell Strip? 

As promised, here are a few plants that are tough enough for the most common boulevard conditions, are typically 3’ (1m) tall or less, sorted by growing conditions. This list is by no means exhaustive but is meant just to get you started.  

Dry, well drained soils, full sun 

Full sun garden requires drought tolerant, tough plants. Photo courtesy of Donna Slater.
  • Achillea millefolium (Yarrow) 
  • Aquilegia canadensis (Wild Columbine) 
  • Asclepias tuberosa (Butterfly Milkweed) 
  • Bouteloua curtipendula (Side-oats Grama) – grass  
  • Ceanothus americanus (New Jersey Tea) – shrub 
  • Coreopsis lanceolata (Lance-leaf Coreopsis) 
  • Eragrostis pectinacean (Purple Lovegrass) – grass 
  • Fragaria virginiana (Wild Strawberry) 
  • Geranium maculatum (Wild Geranium) 
  • Geum fragarioides (Barren Strawberry) 
  • Geum triflorum (Prairie Smoke) 
  • Penstemon digitalis (Foxglove Beardtongue) 
  • Penstemon hirsutus (Hairy Beardtongue) 
  • Pycnanthemum virgianum (Virginia Mountain Mint) 
  • Rudbeckia fulgida (Orange coneflower) 
  • Rudbeckia hirta (Black-eyed Susan) 
  • Schizachyrium scoparium (Little Bluestem) – grass 
  • Solidago nemoralis (Gray Goldenrod) 
  • Solidago rigida (Stiff Goldenrod) 
  • Sporobolus heterolepis (Prairie Dropseed) – grass 
  • Symphyotrichum oolentangiense (Sky-blue Aster) 

Dry, Shade to Part Shade 

Part sun/Part shade usually means 4-6 hours of direct sun each day. Photo courtesy of Donna Slater.
A narrow, part shade garden that will eventually become full shade as the trees mature. Photo courtesy of Victoria Hunter Williams.
  • Antennaria parlinii (Parlin’s or Smooth Pussytoes) 
  • Asarum canadense (Wild Ginger) 
  • Asclepias exaltata (Poke Milkweed) 
  • Campanula rotundifolia (Harebell) 
  • Elymus hystrix (Bottlebrush Grass) – grass 
  • Eurybia macrophylla (Largeleaf Aster) 
  • Geranium maculatum (Wild Geranium) 
  • Geum fragarioides (Barren Strawberry) 
  • Oenothera biennis (Evening Primrose) 
  • Penstemon hirsuta (Hairy Beardtongue) 
  • Phlox divaricata (Wild Blue Phlox) 
  • Polygonatum biflorum (Solomon’s Seal) 
  • Tiarella stolonifera (Foamflower) 
  • Solidago flexicaulis (Zigzag Goldenrod) 
  • Solidago ptarmicoides (Upland White Goldenrod) 
  • Viola pubescens (Downy Yellow Violet) 

Heavy Clay Soils, Full Sun Part Shade 

  • Achillea millefolium (Yarrow) 
  • Allium cernuum (Nodding Wild Onion) 
  • Asarum canadense (Wild Ginger) 
  • Asclepias incarnata (Swamp Milkweed) 
  • Carex blanda (Common Wood Sedge) – sedge 
  • Carex glaucodea (Blue Wood Sedge) – sedge  
  • Coreopsis lanceolata (Lanceleaf Coreopsis) 
  • Elymus hystrix (Bottlebrush Grass) – grass 
  • Fragaria virginiana (Wild Strawberry) 
  • Geranium maculatum (Wild Geranium) 
  • Geum fragarioides (Barren Strawberry) 
  • Monarda didyma (Beebalm) 
  • Monarda fistulosa (Wild Bergamot) 
  • Pycnanthemum virginianum (Virginia Mountain Mint) 
  • Rudbeckia fulgida (Orange coneflower) 
  • Rudbeckia hirta (Black-eyed Susan) 
  • Solidago flexicaulis (Zig-zag Goldnerod) 
  • Symphyotrichum lateriflorum (Calico Aster) 
A full shade garden gets less than 4 hours of sun a day. This full shade garden is thriving with the right mix of shade plants. Photo courtesy of Pete Ewins.

A special thank-you to all the folks that offered up photos of their boulevard gardens to make this article possible.

Happy Native Plant Gardening