If you garden under large trees, especially beneath Toronto’s numerous Norway Maples, you have four problems.
First: Norway Maples cast a deep shade, perfect for keeping the street or dwelling cool, but limiting what you can grow underneath it. So breeze right past those plant tags with the “full sun” icons.
Second: Norways have shallow roots that fill the top few feet of topsoil in your garden in a fibrous mass. Digging soil is hard enough, but tree roots make the task arduous: you have to slice through the roots with every dip of your spade. Soil clumps often come up in solid shapes. (Upside is, after such a workout, you can have that extra chocolate chip cookie with impunity)
Three: The leaf canopy acts like an umbrella, so when you do get showers, the rain stays mainly where the tree isn’t. You can’t depend on rainfall alone in a dry shade garden. Irrigation is a must, at least spot irrigation, especially until the plants are established.
Four: Your perennials are on an enforced diet. Rain falls, tree roots suck it up. Soil amendments added, the tree gets first pick. Plants and soil are constantly undernourished.
Extra irrigation, yearly soil amendment with compost, and completely replenishing the garden every few years help mitigate the problem. But choosing the right plants in the first place is the key tool in the dry shade garden. Forget day lilies, roses, peonies and siberian irises. You need adaptable plants that can tough it out.
Good Perennial choices for dry shade:
Rudbeckia Triloba, Lamium, Nepeta (ornamental catnip), Shasta daisy, Some hostas (the ones with thick, leathery leaves are best) Sweet Woodruff, Geranium Macrorrhizum, Epimedium, Lychnis coronaria, Heuchera, Bergenia and Hellebores are good choices. Lily of the Valley works well as a ground cover, and it comes in an attractive variegated form that keeps it interesting all season. Vinca is another reliable choice.
Spring Bulbs: tulips, (treat as annuals, unless you use species varieties, like tulip tarda), hyacinths, species crocus, scillas, grape hyacinths, anemones. Stay away from daffodils, unless your shade is dappled.
Do you suffer from the ultimate gardener’s challenge, dry shade? Let us know what works for you in the comments.