'We hit 115 [degrees] here last July, and the rock rose and lavender did fine," says Don Schultz, horticulture manager for the Water Conservation Garden at Cuyamaca College. In the desert, where temperatures recently reached 120 degrees, Schultz says native plant life should have no problems. "The barrel cactus, for example, would survive. It's native to very hot areas and will take it as hot as you can give it." On Saturday, July 21, the Water Conservation Garden will conduct a class on xeriscaping, or landscaping with low-water-use plants. The term "xeriscape" — from the Greek word xeros, meaning "dry" — was coined, copyrighted, and trademarked by the Denver Water Department in 1981. But it doesn't mean all dry — according to xeriscape.org, to xeriscape means to apply water in "well-controlled amounts and locations in the landscape."
"People think that palms, like the queen palm, need a lot of water, but they don't," says Schultz. "They think because palms and some flowers, like the bird-of-paradise, are tropical, that you've got to water them a lot. I water them about once a week, even in the summer; I water them a couple of inches a month." Schultz measures water by inches rather than time for the sake of consistency. "Sprinklers, how they're installed, how far apart they are, what kind of nozzles are used — there are so many factors that can cause a lot of variations. I run [the sprinklers] here for 15 minutes, but if you ran yours for 15 minutes, you could be putting much less water down than mine." To measure in inches, Schultz places measuring cups in the areas he waters. "Instead of waiting for the rain, turn your sprinklers on and see how long it takes to put down half an inch."
Cacti and succulents are often overwatered. Once the acacia tree is established, it only needs water once a month. "If the soil is too wet, California native plants can get diseased," Schultz explains. Two such plants are the manzanita (a shrub) and the ceanothus (or California lilac). "The way they get through the summer is they go deciduous and look like they're dead. Imagine the plants on the hills, nobody's watering them, and they get through the summer. When you start watering them, they are susceptible to all these disease organisms that like moisture. The plant didn't evolve in that situation, so they have no resistance."
Choosing the right kind of soil can help gardeners avoid accidental overwatering. "If you have clay soil that holds water really well and doesn't dry up, you are much more prone to overwater. If you have real sandy soil, you'd have a hard time killing plants." Schultz adds that any plant can be killed by overwatering -- even aquatic plants can drown if they are not exposed to the right balance of soil to water.
Like other plants, some xeriscape plants require skilled maintenance to look their best. "Some plants need to be pruned strategically." Schultz describes the Cleveland sage as an example. "It's the sort of plant that once it blooms out, toward the end of the summer, it's gotten to be kind of long and leggy. When it gets into fall, it starts to put out new growth in the base. By that time, you want to prune back to the new growth, about half the length of the stem, creating fresh new growth...
"Over 90 percent of the lawn going into any kind of new construction you see is tall fescue grass," says Schultz. "That's the standard grass that you see stacked in sod outside of Home Depot." Bermuda grass and zoysia grass use about two-thirds of the water needed for tall fescue grass. Whereas the fescue grass stays green year-round, lower-water-use grasses lie dormant in the winter, turning brown in the shade or in cool weather. "On the coast, they lose some color but don't go completely brown," says Schultz.
Schultz says it's difficult to give general advice on gardening in Southern California. "There are many different climate zones just in this small area, and that does complicate things." Kangaroo paw may flourish along the coast but not do as well inland, in contrast to the hot-summer-, cold-winter-loving crepe myrtle. However, Schultz points out that caring for drought-resistant plants is not as difficult as maintaining plants that require a lot of water, such as roses, hydrangeas, or azaleas. "A lot of xeriscape plants are native to climates similar to ours. You can just go ahead and put them right in the soil." -- Barbarella
Xeriscape: Beautiful Landscape on a Low-Water Budget Saturday, July 21 9:30 a.m. to 12:30 p.m.
Water Conservation Garden at Cuyamaca College 12122 Cuyamaca College Drive West El Cajon Cost: $12 members, $15 nonmembers Info: 619-660-0614 or www.thegarden.org