|Vibrant gardens with minimal water usage
Gardeners in the Russian River watershed are so fortunate. We can grow a tremendous variety of plants, and we can do it with very little water.
Choosing the right water-thrifty plants and incorporating good garden practices are key to having beautiful diverse gardens while still being good stewards of our water resources.
Garden practices that make the most of our water resource are especially important during this drought year. The first step is to make sure your garden soil is as “drought tolerant” as possible. Adding a generous layer of organic mulch on all exposed soil areas is the best thing you can do.
Mulch keeps water-thirsty weeds down, adds a steady supply of nutrient-rich organic matter (which holds soil moisture), increases infiltration of rainfall and irrigation, reduces water loss through evaporation and keeps soil temperature stable. Good organic mulches include fallen leaves, wood chips, and compost. A “generous” layer is 4-6 inches deep.
The next important garden practice is to apply water when needed to the root-zone of the plants at a rate the plants can use the water. We typically have little if any rain from May to October (the growing season for most plants), so we need to irrigate all but the most drought-resistant plantings during the summer. In the Russian River watershed, thirsty plants like turfgrass require about 36 inches of applied irrigation each year. Luckily, most plants from our native flora, as well as many plants from other Mediterranean climates worldwide, require no more than 12 inches of applied water each year. Knowing the “water appetite” of your plants means you can water only what is needed. Thanks to the University of California Cooperative Extension, we have a resource that lists this “water appetite” of virtually all garden plants in California – the Water Use Classification of Landscape Species (WUCOLS) report at http://ucanr.edu/sites/WUCOLS/.
Because our water supply is so limited this year, do not put in new plants until after the first autumn rains if possible. While maintaining your current garden or planning for future additions, here are some great candidates to consider for your garden:
• Deciduous shade trees for yards or streetscapes – Chinese Pistache (Pistachia chinensis) with intense red and orange fall color; Crepe Myrtle (Lagerstroemia) with vibrant late-summer flowers and striking bark; or Maidenhair Tree (Ginkgo biloba) with incomparable yellow fall leaves.
• Flowering shrubs – Red-flowering Currant (Ribes sanguineum), one of our most striking California natives with pink to red flower in early spring; summer flowering Rockrose (Cistus) from southern Europe; or one of the many Lavenders (Lavandula), which flower from spring through summer.
• Cut flowers – Penstemon in red, pink or blue; Yarrow (Achillea) with white, yellow or crimson colors; any of the many varieties of Daffodil (Narcissus); deep yellow (Coreopsis); and the sunburst of orange and yellow of Blanket Flower (Gaillardia grandiflora).
• Formal hedges – Myrtle (Myrtus communis), a wonderful dark green substitute for the more thirsty boxwood; Lavender Cotton (Santolina) creates a low grey or dark green fine-textured hedge; and Italian Buckthorn (Rhamnus alaternus) works for taller hedges, either sheared or unsheared.
• Edible landscapes – any variety of plum (Prunus) or persimmon (Diosporus); table or wine varieties of grape (Vitis); pomegranate (Punica); olive (Olea); and the South American shrub pineapple guava (Feijoa sellowiana), with edible flowers and fruit.
• Herb gardens – either prostrate or upright rosemary (Rosmarinus officinalis); culinary sage (Salvia officinalis); any variety of thyme (Thymus); and the evergreen European shrub or tree, Sweet Bay (Laurus nobilis).
• Wildlife gardens – Butterfly Bush (Buddleja) with striking summer flower; Coyote Bush (Baccharis pilularis), a native which hosts numerous beneficial insects; and Pacific Wax Myrtle (Myrica californica) which birds flock to for the tiny waxy berries.
As you introduce water-thrifty plants into the garden, remember to group them together so they can be watered according to their water appetite – a practice called “hydrozoning.” Consider installing efficient drip irrigation, which most of these plants prefer to overhead spray irrigation. The result will be both beautiful and water efficient – a real win. And don't forget to mulch, mulch and mulch some more.
Virginia Porter, Executive Director of RRWA, penned this article. RRWA is an association of local public agencies in the Russian River Watershed that have come together to coordinate regional programs for clean water, fisheries restoration, and watershed enhancement.