Q. I am a religious reader of your column. You give so much helpful information. However, it would be most helpful to me, and possibly others, if you would also include in your discussion of plants their sun requirements. My property has mostly shade, so I am quite limited.- Sandy Coven, Woodland Hills
A. I am flattered by your religious commitment to reading this column, even if it is misplaced. By the same token, I could perfectly understand a religious commitment to plants, which are surpassed only by God in terms of their life-sustaining qualities and ubiquity. Plants are responsible for the air we breathe, the food we eat, the clothes we wear and the structures we call home.
As for their sun requirements, most plants in the San Fernando Valley, including roses and many succulents, cannot handle all-day sun. In the San Fernando Valley, full sun exposure stresses every sort of plant, including many California native species. After years of frustration with ceanothus and manzanita, for example, I began giving them no more than half a day of direct sun and they have thrived ever since.
Therefore, having “mostly shade,” especially in an era of tight water budgets, could be a blessing. At the same time, you have to make a distinction between dappled light or partial shade, such as that created under a single tall, open-branched tree, where you can grow a wide variety of plants, and the deep shade or shadows cast by several trees or structures, in which it may be nearly impossible to grow anything except spider plants (Chlorophytum comosum). These classic, low-maintenance, indestructible indoor favorites also may be grown outdoors where shade is so extreme that not even ivy will grow.
Although spider plants come from the tropics, the protection afforded by dense tree cover will provide a significant extra measure of heat on cold nights.
Spider plants also have a redoubtable tuberous root system so that even when their foliage is blackened by frost, they will invariably sprout new leafy growth in the spring. Several types of spider plants are available, some striped on leaf margins and some striped on leaf midribs. Stripes may be wide or narrow and are available in pure white, creamy white or yellow.
Warning: Spider plants, although outstanding for erosion control on slopes and in most shady locations, are highly invasive and will suffocate other plants in their vicinity. So make sure you plant them in an area devoted exclusively to their proliferation.
Umbrella plant (Cyperus alternifolius) is an equally indestructible shade plant. It is both clumping and self-sowing and grows to around 4 feet tall. When it begins to look ragged, chop it back to the ground. It is guaranteed to grow again, achieving and even surpassing its former stature.
When selecting plants for sun or shade exposure, it is vital to be aware of how the amount of light reaching your garden changes from one season to the next.
Under a deciduous tree, for example, winter exposure might be all-day sun, but after the tree leafs out in the spring you are suddenly talking about half-day sun or shade. Such an exposure is ideal for ‘Red Wing’ or ‘Red Bird’ azaleas, whose flowers are actually more fuchsia than red and seem to be in bloom practically every day of the year. A well-mulched azalea in a shady location should not need to be soaked more than twice a week, even in hot weather. Ideally, it would be watered with laser-drilled drip irrigation tubing to minimize water use.
Any plant on display at the nursery now, planted in full sun, will do fine as long as temperatures stay cool and days are short. Once warmer weather arrives, however, and days lengthen, many of these winter beauties would have to be moved to a less sunny exposure.
Certain plants that grow from bulbs, tubers or rhizomes, such as ‘Paper White’ narcissus, will naturalize a partially sunny to moderately shady area.
For a winter botanical fragrance, no plant surpasses ‘Paper White’ narcissus. When used as a cut flower in a vase, its scent is so strong that it will easily overpower any other odors in the vicinity.
Jonquils, which start blooming in late winter in white or yellow, are miniature daffodils with a spicy smell.
Leucojum vernum, or spring snowflake, is a tough shade lover with nodding, bell-shaped white flowers whose petals are tipped in green. This bulbous, rapidly spreading perennial is distinguished by its capacity to grow in damp, heavy soil.
Diascia, although an annual, has been hybridized to the point where it stays in bloom for many months and may be planted throughout the year. It does fine in lightly shaded exposures. It is a snapdragon relative and so is partial to well-drained, well-composted soil. Diascia (dy-ASS-ee-ah) is available in various shades of red, pink, magenta and violet, as well as in white.
Tip of the week
If you want to see constant color in your garden throughout the winter, consider planting ornamental cabbage and ornamental kale and collards, common names for nonheading, hardy types of cabbage. Unlike pansies, primroses and snapdragons, ornamental cabbage and kale can persist easily until spring. The beauty displayed by ornamental cabbage and kale is temperature-dependent. The colder the winter, the more stunning the plants.