Face Up to Shade
Could Your Garden Be Less Sunny Than You Think?
By Rachel Foster 8/12/04

Shade has been on my mind lately. We miss our sick old plum tree, which used to provide a nice cool place to sit in the garden and read. And I've been appreciating the fact that, given shade, you can even work outside on a hot afternoon in reasonable comfort. Shady gardens also wait more patiently for water: It's rare that a few more hours of drought will mean death to a plant that's growing in the shade.
This is also a time of year when I am reminded, when something planted hopefully in spring turns leggy and fails to bloom, that shade is not always benign. Even after years of shade gardening, I can still make the same old mistake. This year I planted a small-leafed rhododendron under leafless Japanese maples. Only after the trees leafed out did I realize it will never bloom there or even make a nice plant. I should have chosen a more shade-tolerant variety.
At least I recognize the signs of light deprivation when I see them. I think many gardeners consistently underestimate the impact of shade on their gardens. People who ask me why their plants are doing poorly are usually surprised if I suggest they are just not getting enough light. I've even seen hybrid tea roses struggling under trees, while the owner protests "but they always did fine right here." Time passes, trees grow. These gardeners are in denial.
Shade denial is sometimes just a case of wishful thinking: We want to grow plants we know and love, and these are often sun-loving. Only a fraction of the plants we grow actually need full sun, thank goodness, in spite of what it says on the labels. But the majority of plants we grow for their flowers need at least five or six hours of direct sun under open sky. How can you tell when plants aren't getting enough light? They grow slowly, even with plenty of water. Stems tend to be few, tall and spindly, with leaves that are farther apart than you expect. And the plants fail to bloom well.
Whatever the cause of shade denial, it's result is always disappointment. Face facts, and you stand a chance of a beautiful garden. If you don't believe me, go to a library and check out The Natural Shade Garden by Ken Druse. Drool over the pictures, and embrace these principles of gardening, never more valuable than in shade: Leaves matter. Structure and texture are paramount. Green is many colors. Then prepare to learn about a whole new set of plants.
Look at other shady gardens, lots of them, and forests, too, and get in the habit of looking up at the sky to see what the plants see. Once a plant gets much less than half a day of sun, reflected light from open sky can be much more important than direct sunlight. Watch the garden throughout the day in spring and summer to identify the brightest places. You may want to reserve these for a few plants with showy flowers, or sun lovers with interesting leaves that are worth growing even if they won't bloom.
Where grass does not appear on its own and violets are your only weeds, it's a sure bet you are dealing with full shade! The ground under mature trees can be dry as well as dark. The depth and type of tree roots influence the level of soil moisture, which in turn influences plant choice. Native woodland plants, large or small, are well adapted to droughty conditions among tree roots. Plants with bulbs, tubers or thick fleshy roots, like hostas, don't mind drying out between waterings; astilbes hate it, and may never thrive in ground full of thirsty tree roots.
Plants that receive less than half a day of sun would rather get it in the cool of the morning. Plants that withstand hot afternoon-only sun the best are succulent or hairy, like sedum or lamb's ears, or have strap-like leaves -- grasses, day-lilies and irises, for example. Large, thin leaves will grow most beautiful in constant light shade or cool morning sun, so save space with those conditions for things with particularly gorgeous foliage. Next month I will write about some of my own favorite plants for different types of shade.