Marin IJ Articles
September 19, 2009
Shaded places often worry the amateur gardener. What will grow? In fact, there are many plants that thrive all the better for shadows.
There are certainly degrees of shadiness; the ideal may be a "broken light," where the shadow is not too dense, but sufficient to give protection from the hottest rays of the sun.
If you prefer shrubs the choice is wide: Azaleas like a lime-free soil and if you have room, rhododendrons and camellias, which enjoy the same conditions, are available in many lovely colors. Some species of Daphne grow well in the shade. And new, shade-loving varieties of hydrangea (unlike the "old lady white wig" ones of yesteryear) are now available.
For shaded borders there are several hellebores, which go by the names of Christmas rose (Helleborus niger) and Lenten rose (Helleborus orientalis). They both fill up odd spots and give flowers at a time of year when color is rare. Their demands are few; they like a cool place, a fairly heavy soil and if it is moist so much the better. The one thing they will not stand for is a poor sandy soil, which will dry out in the summer. As an evergreen their leaves are handsome and fulsome. The Christmas rose is ideal for picking and lasting for weeks indoors (if you split the stems).
Upright fuchsias requiring a bit of sun are excellent companions to hellebores and provide color during the summer.
Before there can be any further suggestions for plants in shade provided by trees, the nature and health of each tree must be considered: An oak, for example, requires privacy from 6 to 12 feet. There should be little disturbance of the oak's root zone and little soil movement. Remember, too, that oaks like to be dry during the summer, so that would exclude many flowering shrubs. You might consider a few perennials that would be compatible and offer a bit of color: day lilies (Hemerocallis species), Iris douglasiana, coral bells (Heuchera species) and don't overlook the sword fern (Polystichum munitum), which also requires little water.
You've probably heard that nothing grows under redwood trees, but if you've had the pleasure of visiting Muir Woods, or some of our other local forests, you have seen that this is not true. Even in the darkest shade you'll see redwood sorrel (Oxalis oregana), sword ferns and a few shrubs that are compatible. Consider ground covers. Besides the sorrel there is the redwood violet (Viola sempervirens), an evergreen with bright yellow flowers, or false lily-of-the-valley (Maianthemum dilatatum), a thick ground cover that likes wet soil.
Vita Sackville-West, creator of the celebrated Sissinghurst garden and a long-time garden columnist for the London Observer, made the "white-shaded garden" very popular. There is something about white shrubs and flowers in the early evening, the crepuscular time of day, that seem almost magical. Picture azaleas, rhododendrons, camellias and foxgloves. In the right location all these white plants might do well in your Marin garden.
But here's another, simpler, consideration. Someone once said that "trees are the lungs of the garden." The description would certainly seem true this time of year - late summer and early fall when our hot days call for a cool breath of air. A shady spot under trees may be enjoyed without benefit of other plants. Perhaps a few pots of shade-loving flowers (impatiens, lobelia, begonia) will do and a comfortable place to sit with a book or companion and a bit of iced tea, lemonade or stronger libation.
The University of California Marin Master Gardeners are sponsored by UC Cooperative Extension. For questions about gardening, plant pests or diseases, call 499-4204 from 9 a.m. to noon, and 1 to 4 p.m. weekdays, or bring in samples or pictures to 1682 Novato Blvd., Suite 150B, Novato.