The dappled light on a shade bed nicely sets off the woodland flowers that flower in spring – it’s a symphony in blue and yellow right now, with the Virginia Bluebells (mertensia virginica) at their glorious peak.
What a joy these are! They’re slowly spreading across the bed – one clump has turned into three over the past few years, with little seedlings promising more to come. Behind, a lovely clump of Large-flowered Bellwort (uvularia grandiflora), which is about the same height and shape as the bluebell, but with a completely different look to its foliage and yellow flowers that dangle singly, not in clusters.
Beginning to come into its own after being set back by frost is a Bleeding Heart (dicentra spectabilis) cultivar called ‘Gold Heart.’ It’s not in flower yet, but the wonderful yellow foliage is a beacon in the shade.
Nearby, the Woodland Phlox (phlox divaricate) has just come into flower. It has one of the best blues, soft and luminous.
When I first cleared this space, years ago, it was an unpromising pile of weedy sand, left from some building project. I planted Periwinkle (vinca), which I had seen in local woods and assumed to be native and knew to be “easy.” Yes, it was easy, but alas, not native.
It’s an alien invader, inimical to native wildflowers like the bluebells and bellwort that have replaced it. I took it out, but as is often the case with such mistakes, I have to remain vigilant and still find the occasional periwinkle shoot sneaking its way across the ground.
Back then I had little idea of what to put in a garden. The idea of creating a community of plants that are native to this area would not have occurred to me. As I muddled through, guided (and often misguided) by friends and magazines and memories of gardens from another continent, I would have been grateful to have been warned against some of the species that seemed so beguiling in the garden centre.
These are some of what I have planted, have struggled to eradicate, and would advise against because they are fearful spreaders and can escape our gardens and present a threat to native biodiversity:
1.Non-native ground cover: Periwinkle (vinca), Bishop’s Goutweed (aegopodium podagraria). Crown Vetch (securigera varia), Bugleweed (ajuga), English ivy (hedera helix)
2.Non-native perennials - beautiful but bad: Bellflower (campanula), Gooseneck Loosestrife (lysimachia clethroides)
3.Non-native shrubs and vines: Species lilac, bush honeysuckles, shrub roses (rosa multiflora and rosa rugosa), Oriential Bittersweet (celastrus orbicultus)
4.Non-native trees. Norway maple (acer platanoides), Russian Olive (eleagnus augustifolia), Mountain Ash (sorbus occupata), White Mulberry (morus alba). Native alternatives: Sugar, Red, Black, Silver, Striped or Freeman’s maples; Silverberry (eleagnus commutata); American Mountain Ash (sorbus americana); Red Mulberry (morus rubra)
The Ontario Invasive Plant Council has an excellent booklet, ‘Grow Me Instead,’ which lists good native alternatives to problematic garden plants.
There are native plants that are pretty invasive. Sometimes, that's just what you want - something vigorous to fill a hot dry spot. Sometimes you have to be careful because they don't play nicely with more delicate species. Set physical limits - like paving - to their space. Here are three examples:
-Spiderwort (tradescantia): I love this three petalled perennial. The species is blue and there are cultivars in white and purple. It needs its own space in the sun, planted away from anything that might be bothered.
-Smartweed (polyginum): this is a wetland plant with attractive pale pink bottlebrush flowers. I have it in a hot, dry spot where it stays under control if I whack it back every year or so.
-Milkweed (asclepias): every gardener should plant milkweed, the host of the monarch butterfly. Most of the family is well-behaved but the common milkweed (asclepias syriaca) is over-enthusiastic in its habit of sending out underground shoots. It’s nice to have if you can provide some space for it to do its own thing. Otherwise, go for the very beautiful pink Swamp Milkweed (asclepias incarnata) or the striking orange Butterfly-weed (asclepias tuberosa), which are both easy to find in nurseries. There are half a dozen other milkweeds in Ontario, all worth having if you can find them.