By Denise Seghesio Levine, UC Master Gardener of Napa County
Summer is bold and bright and warm and colorful. Except when it is not. The other side of summer is soft and gray and fuzzy. Bright, bold summer days are often tempered by soft gray fog creeping over the hills and wispy fingers of silver mist drifting through the valley in the morning, cooling and soothing.
In our gardens we can have the same bold and soft summer contrast. Summer is the time when the most colorful flowers show off: golden sunflowers; circus-colored zinnias; blue, white and red petunias; purple foxglove; red and pink asters. Dahlias and roses, lobelias and nasturtium, four o'clocks and cannas can take center stage.
With so many colors, shapes and scents, we can almost overlook the usually smaller-flowered silver and gray plants. But cool silver and gray are welcome in the garden, especially in our warm summers. Plants with fuzzy silver and gray foliage are made for our Mediterranean climate.
Why, you may ask? It is the fuzz. Look closely at these plants and you will see soft, tiny hairs covering one or both sides of the leaves. These hairs reflect the sun's rays, slow water evaporation, protect the plant from wind and cool the surface of the leaves by several degrees. Thanks to their fuzz, these understated plants are protected from brutal heat and scarce water.
Some botanists suggest that the same hairs that protect from heat also insulate from extreme cold and help keep the plant warm in winter. Herbivores are deterred by these waxy or hairy coatings, making these plants deer resistant. A plus for country gardeners.
At the garden center, it's easy to spot these silvery plants. Look for dusty miller (Artemisia stelleriana) with its lacy foliage. Or lamb's-ear (Stachys byzantina), a perennial with large, soft, fuzzy leaves that children and adults love to pet. Lamb's-ear spreads into a wide gray blanket, producing tall spires of yellow or lavender flowers.
Yarrows (Achillea ageratifolia), mugwort (Artemisia) and many sages, including Salvia argentea and Salvia officinalis, make beautiful counterpoints to neighboring plants with deep green foliage. Sages range from low-growing groundcovers to towering plants with landing pads for hummingbirds and flowers; many are wonderfully fragrant. The one exception I have found is Mexican sage which grows about three feet tall and produces lovely purple flower spires. It has survived and thrived in my garden for 35 years and looks good most of the year. But it smells terrible.
Wooly thyme and others in the thyme family belong on any list of gray-, white- and silver-leaved drought-resistant, unfussy plants. About the only way you can kill these plants is with too much kindness. These are not the sort of plants that require abundant water and compost. They will do much better in spare circumstances with scant water.
If you are perusing seed catalogs, the botanic name will help you identify these plants. White, gray and silver foliage plants have a nomenclature all their own. In Gardener's Latin: A Lexicon by Bill Neal (Algonquin Books),you will find lists with botanic descriptions for the rest of us.
The phrases alb, alba or albi in a plant's genus or species name all signify white. Candicans, eri, erio and floccosus all describe leaves that are wooly. Argent, argyro and argophyllus mean silver leaved. Greicius and incana refer to gray. Hirsutis, comosis and trychopfollus indicate a hairy plant, and arachnoides means spider-like or covered with long scraggly hairs like cobwebs. See? A whole different vocabulary. Neal's lists are extensive in his useful little book, which is still available if you are so inclined.
The madrone tree (Arbutus menziesii) provides another interesting example of the reflective qualities of these plants. Its leathery leaves have furry silver undersides that are so reflective that, on country roads late at night, they can be mistaken for oncoming headlights.
Not every white plant is drought resistant. In nature, plants evolve to survive, but humans now breed plants to be beautiful as well. So be aware that hybridized plants with white foliage may not be as tough as those produced by natural selection.
Next workshop: “Rose Care” on Saturday, June 1, from 9:30 to 11:30 a.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. For more details & online Registration go to http://napamg.ucanr.eduor call (707) 253-4221.
The UC Master Gardeners are volunteers who provide UC research-based information on home gardening and answer your questions. To find out more about upcoming programs or to ask a garden question, visit the Master Gardener website (http://napamg.ucanr.edu) or call (707) 253-4221 between 9 a.m. and noon on Mondays, Wednesdays or Fridays.