The Dry Garden: Green plants that survive gray water
At a packed hall of the Los Angeles County Arboretum & Botanic Garden last week, native-plant specialist Carol Bornstein was asked how native plants would do in landscapes irrigated by reclaimed water.
The occasion was a conservation forum held by the Los Angeles County Department of Parks and Recreation. As irrigation systems switch from potable to reclaimed water, one issue that Southern Californian park keepers had for Bornstein was: Could native plants tolerate the salt in water that is various shades of gray?
Bornstein, co-author of "California Native Plants for the Garden," had no idea. The beauty of native gardens is that besides the brief period when they are getting established, many don’t need irrigation in the summer.
So Bornstein did what any diligent horticulturist would do. She found 13 public gardens using reclaimed water in the summer in her hometown of Santa Barbara, and she listed the native plants doing well in those gardens. Her list may be as useful for home gardeners as it is for park-keepers, particularly with planting season coming and more Southern Californians looking to recycle their gray water for use in the landscape. So, with thanks to Parks and Rec, click to the jump for an edited version of Bornstein's list:
Field sedge or Carex praegracilis, pictured at top. Though a sedge and not a grass, this plant may be used as lawn and even mowed for low-tufting cover. In Bornstein’s photo, field sedge was difficult to distinguish from a classic turf-grass lawn.
Canyon prince giant rye or Leymus condensatus Canyon Prince. A display-worthy mounding grass with blue-green foliage. It needs little or no supplemental water but should be cut back every couple of years.Deer grass or Muhlenbergia rigens. A graceful mounding grass, pictured at right.
Salvias. “We have about 20 species,” Bornstein said. “I was happy to see several of these in many of the landscapes I visited.” They included purple sage or Salvia leucophylla; purple Cleveland sage or Salvia clevelandii, pictured above; and hummingbird sage or Salvia spathacea. Although the first two prefer well-drained soil, Bornstein said, the last would do well planted beneath coast live oaks. She is not sure about how coast live oaks would do with salty water.California fuchsia or Zauschneria californica (also called Epilobium canum). It's attractive to hummingbirds, and it flowers during the long hot months when not much else is in bloom.
Coyote brush, dwarf chaparral broom or Baccharis pilularis. Mounding shrub with bright green foliage and sweet-smelling fall flowers. No supplemental water needed.Quail bush or Atriplex lentiformis. Native to coastal bluffs, quail bush (also called salt bush) is salt tolerant and highly valuable for native butterflies and birds.
Coffeeberry or Rhamnus californica. There are many forms of this berry-studded evergreen from mounding ground-covers to imposing shrubs.
Manzanita or Arctostaphylos. Bornstein cited three cultivars, including Arctostaphylos densiflora Howard McMinn. “Wonderful for winter flowers and showy little apple-like fruits and beautiful sculptural limbs,” she said.
Toyon or Heteromeles arbutifolia. “Most people love toyon because of the beautiful berries that color up at Christmas time,” Bornstein said. They may be pruned into a hedge or used as small trees.
Blue elderberry or Sambucas mexicana (sometimes identified as Sambucas nigra mexicana). Has creamy yellow flowers that attract butterflies and clusters of berries prized by many birds.
Ironwood (Catalina and Santa Cruz) or Lyonothamnus floribundus. “Fern like leaves that kind of look like marijuana," Bornstein said. I was really surprised to see this plant doing so well in many landscapes.”
Torrey pine or Pinus torreyana.
Bornstein is quick to note that her survey was a casual first step in an intriguing challenge from L.A. County park keepers. Much remains to be determined about the effect of salts in reclaimed water on native flora. In her book, she defined drought-tolerant plants as plants that will survive hot months without supplemental irrigation. She urges those who irrigate native plants to water during the plants’ natural growing periods, from mid-fall until mid-spring.
-- Emily Green
Green's column on low-water gardening appears here weekly. She also blogs on water issues at www.chanceofrain.com.
Photo credits, from top: Irfan Khan / Los Angeles Times; Robert Lachman / Los Angeles Times; Sean Masterson / For The Times; Francine Orr / Los Angeles Times; Los Angeles Times.