Even hotties need a few showers to cool them off
I should have written this article weeks ago when, despite the daily promise of afternoon thunderstorms, everything was parched. Maybe it was reading about the drought in China, but I was sure we were in for a long dry spell. A native of the Pacific Northwest, I can handle endless rain and fog, but not endless sunshine and lack of rain. So, I have developed tricks that I’m convinced induce rain and I started down the list.
I left cushions out when thunderclouds loomed, grabbed my sunglasses when I walked out the door, packed my umbrella religiously, bought an extra length of hose, drenched my “street” tree, and watered my pots. I stopped short of leaving the Mini’s sunroof open, however. (That, sad to say, actually once produced a copious overnight downpour.)
Nothing worked -- until I sat down to write about drought resistant plants.
Drought resistant or tolerant plants manage prolonged but not eternal dry periods. Some, like sedum, are succulents and retain water. Others are silver and reflect sunlight and some are pubescent (at last, a chance to use this word), meaning they are fuzzy. The fuzz reduces air motion over the leaf, thus minimizing transpiration. Some drought tolerant plants have waxy leaves that slow water loss, and others have taproots that store water. The flip side is, that, these plants often do poorly if overwatered or if planted in heavy wet soil. Sprinkler systems can play havoc with them.
For dry shade, I like epimedium, Solomon’s seal, hellebores, and both the perennial and biennial forms of foxglove (Digitalis). Biennial foxglove does well in shade and sun, and self-sows if permitted to “go to seed”. It blooms every other year, so if you only plant them once, you will have blooms every other year. Plant them two years successively to ensure annual blossoms. Be wild and plant white ones one year and pink ones the next.
Lots of sun-loving plants tolerate dry weather well. Thyme, for instance, which has petite leaves that limit transpiration, prefers to be dry. Since it comes in solid green as well as variegated models, and both have gorgeous purple blooms, you can be quite creative with it: I once saw a miniature knot garden planted with tightly clipped thyme. Other herbs like sage, rosemary, and lavender are great for dry periods, though I will confess that I have killed more lavender than I’d like to admit, probably because I planted it in soil that didn’t drain very well.
Lamb’s ear has sensuous silver pubescent leaves, and is an effective edging plant. It’s texture and color work beautifully in borders with variegated, green leafed, and red leafed plants and needled shrubs. If you are looking for accents, toss in mullein (verbascum). Their broad leaves and tall spikes are dramatic and their tiny flowers are incongruently delicate. Day lilies are great and, like iris, will double as erosion control. Don’t forget Black Eyed Susans (Rudebekia) and Cone Flowers (Echinacea) which have terrific winter structure, according to Dutch plantsman, Piet Oudolf, who also leaves the seed heads to attract birds.
Then there are annuals that are drought resistant and work well in pots, which dry out fast. Waxy leafed ivy geraniums are reliable and they come in different colors. So is lantana, which I especially like because of their citrus-ey fragrance, wide variety of colors, and loose structure. Zinnias do very well in dry conditions, and, in fact, get unsightly powdery mildew if allowed to get too wet.
If you are looking for drought tolerant shrubs for a sunny spot, try rugosa roses. I know they are a little informal and associated with the beach, but they can be stunning in formal urban settings, too, and their fragrance is to die for. Best of all, they are repeat bloomers and when they finish, present lovely deep orange and red rosehips. Cinquefoil (Potentilla fruticosa) is a great long blooming shrub with small white, light yellow, or dark yellow flowers, and you can try pepper bush (Clethra alnifolia) if you want to attract butterflies.
And yes, Virginia, there are drought tolerant trees. One of my favorites is Gingko biloba, which is one of the oldest tree species in existence. Gingkoes, a great street tree, are dioecious. The females bear fruits that are smelly when they fall and very tasty when they are served. Their oddly shaped leaves turn golden yellow in fall. For large gardens I like Golden Rain Tree, (Koelreuteria paniculata), which is blooming now. It’s long-lasting panicles of small yellow flowers turn into lovely brown pods in late summer, offering another interesting texture in the garden. Happily, you can rely on crabapples to be drought resistant as well as the fine-leafed Japanese Zelkova (Zelkova serrata), which has a great dark reddish fall color. These are gorgeous upright, vase-shaped trees that get quite large and were introduced as substitutes for American Elms after Dutch Elm disease decimated them.
All in all, nothing is drought tolerant if it is not well planted or it is planted in unsuitable conditions. Don’t plant your plants too low or too high. Mulch your plants (but never let me catch you using unsightly wood chips, bark nuggets, or dyed shredded plywood). And, if you have an irrigation system, think twice about planting what needs little water. Finally, just because a plant can tolerate drought doesn’t mean it never needs water.
If we are threatened by another dry spell, expect a sequel to this article. There are many more drought tolerant plants to write about and this may be my latest trick to make it rain.