Gardening with native plants
Our wild spaces are being increasingly impacted by encroaching urbanization, agricultural practices and invasive species, with a consequent decline in pollinators, other insects and the insect-eating birds that depend on them. The good news is that you can become part of a movement to arrest that decline by choosing native plants for your garden. And no space is too small to have an impact! A recent study (as reported on CBC Radio, 04/11/22) by award-winning ecologist Lenore Fahrig and her associates at Carleton University has shown that the accumulation of small patches of habitat can be just as important for preserving biodiversity as larger but less numerous patches.
Native plants are adapted to our native soils and have co-evolved with our local insect, bird and mammal populations over thousands of years. They are the foundation of a food web and our insects and birds need these plants to thrive. Studies have shown that our native plants support a greater number and diversity of insects that depend on those plants for food and shelter than do exotic introductions. That is because our plant-eating insects can overcome the chemical defenses found in the leaves of native plants, allowing them to be consumed. However, an estimated 90% of plant-eating insects are specialists, restricted to a narrow range of plants. Some of these relationships become so specialized that a particular species of moth or butterfly can only consume the leaves of one larval host plant, e.g., the monarch butterfly’s exclusive relationship with milkweed.
There may also be a correlation between the availability of insects and the fluctuations in bird populations. Nearly all terrestrial birds in N.A., an estimated 96%, depend on an abundance and variety of insects for migration and breeding and they prefer the protein and fat-laden larvae of butterflies and moths to feed their young.
When you cultivate native plants, you are inviting pollinators, other beneficial insects and birds to share your space, creating a garden that is not just an assembly of colourful blooms and shapes attractive to humans, but one that functions for wildlife as well – a living landscape.
The layered woodland community
In the wild, native shade perennials will usually be part of a woodland community and are just one component of a complex and interconnected layered ecosystem, with each woodland layer providing different ecosystem services and differing habitats for wildlife. If you are gardening in the shade, your garden may already contain plants from the upper layers: one or more trees from the canopy layer and a selection of shrubs in the mid-layer. By including all these layers in your landscape, your garden will provide a great diversity of shelter and food for a wide variety of birds and insects. (For more on the benefits of gardening with native shrubs, see Gardening with Native Shrubs: A Toronto Master Gardeners Guide.)
Although much smaller in vertical size than the tree or shrub layer, the perennial layer is where the greatest variety of flower colour and form is found, with plants of differing sizes, ranging from the taller structural plants through to groundcover plants, occupying different niches and all sharing the same resources of sunlight, moisture and nutrients.
The plants within the perennial layer interact with each other. Perennials are very productive in converting sunlight into plant tissue and recycling nutrients. Spring ephemerals that emerge early in spring will flower, set seed and die, releasing their stored nitrogen back into the soil as other plants are beginning their growing season.
Native perennials have developed important specialized relationships with local fauna as well. They are host plants for insect larvae and provide nectar and pollen to native bees, butterflies and moths. Spring ephemerals are an important source of pollen and nectar for early emerging pollinators, at a time when there may be little else available. And many spring-flowering species, such as trout lily, bloodroot, trilliums and violets use ants to disperse their seeds.
Characteristics of native shade perennials
Perennials that thrive in shade have developed differing survival strategies. One survival tactic of shade perennials is to flower early in the year, before the trees come into leaf. Our spring ephemerals have adopted this strategy, blooming beneath the still-bare canopy of deciduous trees before dying back in the denser shade of summer. Many other native perennials bloom in the spring but have foliage that remains and carries on with photosynthesis throughout the summer. These are plants that devote much of their energy to stems and leaves, rather than colourful summer flowers. Look for those with attractive shapes or the bonus of late summer berries. And a few plants, such as Christmas fern, retain their dark green leaves year-round.
Keep these patterns in mind when planning and planting. Plan for a succession of bloom from spring to fall, with later emerging plants taking over from the early spring bloomers which may be going into dormancy by mid-summer. In this way, you will have a continuous supply of pollen and nectar for pollinators, along with ripening seeds and fruit for birds and wildlife.
Choose plants that will give you a range in heights as well, mingling the taller, structural plants with the ground-hugging lower species. You can add additional texture by using ferns and sedges, many of which are adapted to shady woodland conditions. By using these techniques, you can increase the numbers of species you grow, providing more food, shelter and cover for a wide range of birds and insects.
Planting in masses or clumps of 3, 5, 7 or more of a single species provides a better visual target for pollinators and a mass of food resources in one place.
Choosing your plants
Choosing plants that are suited to your site is always more successful than trying to adapt your site to suit a particular plant. Native shade perennials are adapted to the lower light levels found under the summer tree canopy and benefit from soil with organic matter from accumulated, decaying leaves. By observing plants growing in their natural habitat and plant communities, you will get an idea of how they could be placed with other plants in your garden and which conditions they prefer.
One of the most important factors in choosing shade plants will be determining the amount of available sun/shade. Even within a shady garden, there may be varying levels of shade, ranging from the dappled shade of a lacy tree canopy, such as a honey locust, to the deep shade found beneath evergreens or maples or beside an overshadowing building or wall.
- Partial shade – plants receive 4 to 6 hours of morning or afternoon sun, but should be shaded from the hot, midday sun.
- Full Shade – plants can tolerate less than 4 hours of sun, preferably in the morning. A bright location that receives no direct sun would be classified as full shade.
Exposure to wind is also an important consideration for shade plants: they appreciate a cool environment with higher humidity and may need protection from drying winds.
Native plants should not need additional fertilizer and should be able to endure periods of drought without additional water but it is important to water plants well as they are getting established, especially if they are in direct competition with tree roots.
Buying from local, reputable native plant nurseries ensures that the plants are grown locally: they will be more resilient and adapted to local conditions. (See links below for native plant nurseries.) Generally, native species are more desirable than cultivated native varieties – the “nativars”. Please be aware that nativars may be bred for an “improved” characteristic which makes them less useful to pollinators and insects, e.g., double flowered bloodroot, a sterile cultivar without nectar for pollinators. Nativars are also propagated vegetatively and lack the genetic diversity of species grown from seed.
Garden practice for maintaining a living landscape
- Try to have native plants from each garden layer: the variety of trees, shrubs and perennials is in direct correlation to the abundance and diversity of beneficial insects and birds.
- Plant densely. Plants like to grow in communities, rather than as isolated individuals in a sea of bark mulch, that inhibits the plants’ ability to fill in and thrive. Native groundcovers are particularly useful for suppressing weeds and providing a “green mulch” as they weave through taller perennials.
- Have a source of water for birds and insects. This can be as simple as a shallow dish with some pebbles on the bottom for perching. Keep the dish clean and replenish it with fresh water often.
- Remove any invasive plants. For more information about invasive plants and native alternatives, see the Ontario Invasive Plant Council booklet, Grow Me Instead, and the Toronto Master Gardeners Invasive Species Initiative fact sheets.
- Avoid pesticides which can move up through the food chain. Use organic methods, such as soap spray, only as a last resort. Remember that there may already be beneficial predatory insects, such as parasitic wasps, sawflies, beetles and spiders in your garden, looking for a handy meal.
- Leaf litter can be your gardening ally. It provides shelter for some overwintering bees as well as the pupae of many moths and butterflies which use it as a “soft landing” to complete their life cycle. It is also home to countless other minute organisms, some of which will act as decomposers, returning the nutrients in the leaves to the soil through the cycle of decay. Birds will forage through it looking for food. Leaf litter acts as a mulch protecting the soil from erosion and compaction while helping to retain moisture. It can also protect shallow-rooted perennials from frost-heaving in cycles of freeze and thaw. Best of all, it is free and replenished yearly.
- Take care of your garden soil by digging as little as possible and never when the soil is wet. Avoid walking on your garden beds which also compacts the soil. Avoid synthetic fertilizers and feed the soil from the top down with compost, healthy plant debris and leaf mould laid on the soil surface as mulch, not dug in.
- Don’t be too tidy. Seed heads left in place supply food for birds as well as interesting garden structure. Hollow or pithy stems of some shrubs and perennials can also be nesting sites for bees to overwinter, so leave some in place if you can. Brush piles, tree cavities and fallen logs are all habitats for birds and insects.
- Become part of a larger native plant community in your neighbourhood through a local gardening society or by becoming a member of Carolinian Canada, North American Native Plant Society or Homegrown National Park.
Perennials for shade/part shade
The suggested native perennials listed below are hardy in the GTA. All are useful to local insects, whether as larval hosts or as suppliers of pollen and nectar.
Plants which have notable interactions with pollinators and other wildlife are marked with a P.
Asters (Symphyotrichum), goldenrods (Solidago) and sunflowers (Helianthus) are considered keystone species: plants essential to the food web within our ecosystem.
For more complete descriptions with photographs as well as suggested plant communities and insect associations, please refer to the references listed below.
Spring ephemerals
Cut-leaved toothwort (Cardamine concatenata)
Spring beauty (Claytonia virginica)
Dutchman’s breeches (Dicentra cucullaria) P
Trout lily (Erythronium americanum)
Virginia bluebells (Mertensia virginica)
Rue anemone (Thalictrum thalictroides) P
Red trillium (Trillium erectum)
White trillium (Trillium grandiflorum)
Groundcovers
Canada anemone (Anemone canadensis) P
Wild ginger (Asarum canadense) P
Wild geranium (Geranium maculatum) P
Virginia waterleaf (Hydrophyllum virginianum) P
Canada mayflower (Maianthemum canadense) P
Bishop’s cap or Mitrewort (Mitella diphylla) P
Wild blue phlox (Phlox divaricata) P
Foamflower (Tiarella cordifolia)
Sweet white violet (Viola blanda) P
Canada violet (Viola canadensis var. canadensis) P
Yellow violet (Viola pubescens) P
Common blue violet (Viola sororia) P
Barren strawberry (Waldsteinia fragarioides)
Early to mid-season perennials
White baneberry (Actaea pachypoda) P Note: berries are poisonous to humans
Red baneberry (Actaea rubra) Note: berries are poisonous to humans
Sharp-lobed hepatica (Anemone acutiloba) P
Wild columbine (Aquilegia canadensis) P
Spikenard (Aralia racemosa)
Jack-in-the-pulpit (Arisaema triphyllum)
Blue cohosh (Caulophyllum thalictroides)
False Solomon’s seal (Maianthemum racemosum) P
Starry false Solomon’s seal (Maianthemum stellatum) P
Sweet cicely (Osmorhiza longistylis) P
Mayapple (Podophyllum peltatum) May go dormant in summer drought
Solomon’s seal (Polygonatum biflorum var. commutatum) P
Bloodroot (Sanguinaria canadensis) P May go dormant in summer drought
Wood poppy (Stylophorum diphyllum)
Early meadow rue (Thalictrum dioicum) P
Large-flowered bellwort (Uvularia grandiflora) P
Round-leaved violet (Viola rotundifolia) P
Mid to late season perennials
White baneberry (Actaea pachypoda) P See note above
Black snakeroot or black cohosh (Actaea racemosa) P
Red baneberry (Actaea rubra) See note above
White snakeroot (Ageratina altissima)
White wood aster (Eurybia divaricata) P
Large-leaved aster (Eurybia macrophylla) P
Woodland sunflower (Helianthus divaricatus) P
Great blue lobelia (Lobelia siphilitica)
False Solomon’s seal (Maianthemum racemosum) P
Starry false Solomon’s seal (Maianthemum stellatum) P
Solomon’s seal (Polygonatum biflorum var. commutatum) P
Blue-stemmed goldenrod (Solidago caesia) P
Zigzag goldenrod (Solidago flexicaulis) P
Heart-leaved aster (Symphyotrichum cordifolium) P
Tall meadow rue (Thalictrum pubescens)
Perennials tolerant of dry shade
Wild ginger (Asarum canadense) P
White wood aster (Eurybia divaricata) P
Large-leaved aster (Eurybia macrophylla) P
Wild geranium (Geranium maculatum) P
Canada mayflower (Maianthemum canadense) P
False Solomon’s seal (Maianthemum racemosum) P
Solomon’s seal (Polygonatum biflorum var. commutatum) P
Zigzag goldenrod (Solidago flexicaulis) P
Heart-leaved aster (Symphyotrichum cordifolium) P
Barren strawberry (Waldsteinia fragarioides)
Pennsylvania sedge (Carex pensylvanica)
Bottlebrush grass (Elymus hystrix)
Grasses and sedges
Although grasses, sedges and ferns do not produce nectar for pollinators, they are important as host plants for insects and provide shelter and nesting sites. (For more information on growing sedges, see scorpionfly.ca.)
Common wood sedge (Carex blanda)
Bristle-leaved sedge (Carex eburnea)
Pennsylvania sedge (Carex pensylvanica)
Plantain-leaved sedge (Carex plantaginea)
Broad-leaved sedge (Carex platyphylla)
Stellate sedge (Carex radiata)
Bottlebrush grass (Elymus hystrix)
Ferns
For a selection of native woodland ferns, see Hardy Garden Ferns: A Toronto Master Gardeners Guide.
Resources and references
Darke, Rick and Doug Tallamy. The living landscape; designing for beauty and biodiversity in the home garden. Timber Press, Portland OR, 2014.
Holm, Heather. Pollinators of native plants; attract, observe and identify pollinators and beneficial insects of native plants. Pollination Press, Minnetonka MN, 2014.
Johnson, Lorraine. 100 easy-to-grow native plants for Ontario gardens, rev. 3rd ed. Douglas & McIntyre, Madeira Park BC, 1999.
Johnson, Lorraine and Sheila Colla. A garden for the rusty-patched bumblebee; creating habitat for native pollinators, Ontario and Great Lakes edition. Douglas & McIntyre, Madeira Park BC, 2022.
Dickinson, Timothy et al. The ROM field guide to wildflowers of Ontario. Royal
Ontario Museum and McClelland & Stewart, Toronto ON, 2004.
Canadian Wildlife Federation. Native Plant Encyclopedia.
Credit Valley Conservation. Woodland Plants for Landscaping.
Credit Valley Conservation. Native Plants for Pollinators.
In Our Nature native plant nursery for useful native plant lists and resources.
Ontario Native Plants for plant lists and online catalogue.
Where to buy native plants
Canadian Wildlife Federation. Native plant suppliers list, Ontario.
Credit Valley Conservation. Guide to native plant nurseries.
Date published: April 2023
Prepared by the Toronto Master Gardeners, these Gardening Guides provide introductory information on a variety of gardening topics. Toronto Master Gardeners are part of a large, international volunteer community committed to providing the public with horticultural information, education and inspiration. Our goal is to help Toronto residents use safe, effective, proven and sustainable horticultural practices to create gardens, landscapes and communities that are both vibrant and healthy.
Statement on Invasive Plants: When choosing plants, avoid invasive plants, which can spread quickly and dominate gardens. Invasive plants are sold by nurseries, big box stores or even at community plant sales. Invasives may already be present in your garden. They can invade gardens by spreading from under a neighbour’s fence or may be transported by wildlife. For beautiful, sustainable options to invasive plants, see the Ontario Invasive Plant Council’s “Grow Me Instead – Beautiful Non-Invasive Plants for your Garden” at https://www.ontarioinvasiveplants.ca/resources/grow-me-instead/ before purchasing or accepting “gifts” of plants.
Statement on Home Remedies: The Toronto Master Gardeners do not recommend home remedies, as these have not been proven effective through scientific investigation, and may even damage other living organisms in the soil or plants in your garden. There are other garden friendly options you can use.
If you have further gardening questions, reach us at our gardening advice line 416 397 1345 or by posting your question here in the Ask a Master Gardener section. To book Toronto Master Gardener volunteers for talks, demonstrations, advice clinics, or other services, please contact us at 416 397 1345 or bookamg@torontomastergardeners.ca