As the climate shifts, more gardeners will struggle with too little or too much rainfall
A drought-tolerant front-yard garden in urban California includes the native shrubs coffeeberry and ceanothus.
SAXON HOLT HAS BEEN GARDENING in the summer-dry and winter-wet climate of Northern California for more than 30 years. A noted photographer and co-author of Gardening in Summer-Dry Climates, he’s accustomed to grappling with too much or too little rain. “Where I live, these extremes are our normal climate,” Holt says. And as the global climate continues to change, it’s likely his experiences on the Pacific Coast will be increasingly relevant across much of the United States.
According to National Wildlife Federation Naturalist David Mizejewski, our changing climate will produce more extreme weather in the future. “Many places may be facing extended summer droughts and heavy winter rains,” he says. “We should be thinking about what to plant to best survive these conditions.”
The key, says Holt, is to garden with climate-adapted plants, especially species such as purple prairie clover, a Midwest native that can withstand months without water. He also suggests a diverse range of plants. “That way,” he says, “if some die during extreme events, others will survive.” According to Bethany Bradley, a professor in the University of Massachusetts’ Department of Environmental Conservation, native species are the best choice. “They are more resilient than nonnatives,” she says. Once established, natives need very little supplemental water. And “they increase biodiversity and are better for birds, butterflies and bees.”
All plants need to be watered at some point, however, and how you manage water is critical. “In California, gardeners should be capturing the rain in winter,” says Holt. “A typical roof can collect quite a bit of water,” with 1 inch of rain depositing some 600 gallons onto the roof of an average house. In many parts of the country, homeowners install rain barrels to harvest the rain. One or two barrels will provide some water during dry spells, but for western climates, Holt favors larger cisterns or water tanks. While they are expensive, a single cistern can hold several hundred or even several thousand gallons of water.
Another source of water during dry periods can be your washing machine. With a “laundry-to-landscape” system, the gray water that comes out of a washer is diverted to a yard to water plants. On average, between 10 and 25 gallons of water are generated per load from a front loader and about 40 gallons from a top loader. Such systems are already catching on in California and throughout the arid Southwest.
Both cisterns and laundry-to-landscape systems can require permits and professional help to install. Always check local regulations before starting. If such ambitious undertakings are beyond your capability or budget, however, here are some simple steps that anyone can take:
• Water wisely. “Don’t use overhead sprinklers,” says Julie Weisenhorn, an extension horticulture educator at the University of Minnesota. “The plants need the water applied very slowly at the roots.” She says round soaker hoses are best. Weisenhorn also recommends watering early in the morning so that not much water is lost to evaporation. In addition, whenever possible, try to “hydrozone,” or place plants with similar water needs next to each other.
• Apply mulch. Putting down a layer of mulch about 2 inches deep for herbaceous plants (3 to 4 inches for woody plants) will conserve water and moderate soil temperatures. “Before you use mulch,” cautions Weisenhorn, “watch for bee activity in your yard.” Many ground-nesting bees cannot burrow through mulch. “If you have a lot of bees in your garden,” she says, “leave some areas bare.”
• Know your soil. “One of the most important things you can do is learn about the foundation of your garden,” says Weisenhorn. In most states, the extension offices of land-grant universities will conduct soil tests for individuals for a nominal fee. So will some garden centers. Once you get the results, decide if you need to amend your soil or, alternatively, use only plants that thrive in your existing soil. “Choose plants that grow well in your conditions,” says Weisenhorn. “Otherwise, you are setting them up to fail. The goal is to keep your plants as stress free as possible.”
• Think about the future. If you are planting trees or shrubs that will live a long time, perhaps 50 years or more, look for species that are well suited both to current and projected future climatic conditions in your area, says Mizejewski. Especially consider natives, such as red maple and many oaks, that are resilient and heat tolerant.
According to Bradley, one of the best ways to learn which plants are adapting best to changing climate in your region is to visit native plant nurseries. “Their staff is usually very knowledgeable about local conditions,” she says. Following such advice should help your garden thrive for many years, no matter what kind of weather the future may hold.
Writer and wildlife gardener Doreen Cubie is based in arid Arizona.
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