Drought Tolerant Gardening
By Bob Chapman
Early Franciscan missionaries were the first pioneers of water efficient gardening in the bay area. With few resources available they planted natives and hardy seeds brought in by sea trade in the mission courtyards. Only after advances in well drilling and irrigation technology did landscapes of lush lawns and exotic ornamental plants spread beyond immediate streamsides.
The drought of 1976-1977 devastated landscapes costing millions of dollars in lost plants. Variable water supply, as well as rising energy costs and booming population, reinvigorated drought tolerant landscaping. Today we call this type of landscaping Xeriscape: "Xeros", meaning dry in Greek, and "scape", meaning a type of view or scene. Xeriscaping is developing a slower growing, drought tolerant landscape to conserve water and reduce waste. Not only resource friendly, but also convenient as this type of landscape needs less maintenance: less pruning, feeding, spraying, etc.
Soil preparation and plant selection are the building blocks of a resource friendly landscape. The nature of California soil is either heavy clay or porous sand depending on the location. Rarely are we lucky enough to start with rich loamy soil. Healthy soil is rich, lightly sticks together and holds a moderate amount of moisture. Adding compost to clay soil helps improve drainage and unlocks nutrients. Compost helps sandy soil hold moisture as well as adding desperately needed nutrients. When planting a new shrub or tree a hole twice as wide as the pot and just as deep as the pot should be excavated. Mix roughly 1/3 compost to the excavated soil. Fill the bottom of the hole with this mixture. Remove the pot from the new plant and gently set the plant in this hole. Use the remaining amended soil to fill in around the root mass.
The two steps to plant selection are: choose "un-thirsty" plants and pick the right plant for the place. Don't plant a Rhododendron in full sun on the western side of the house and expect it to perform. Likewise, don't plant a Raywood Ash that will reach 40 feet underneath power lines. Below is a list of hardy, drought tolerant plants. Keep in mind; drought tolerance is a trait of mature plants. Most will need water for the first year. The listed plants are appropriate of the vast majority of Californians, though not all are available all year round. Check with your local Orchard Supply Hardware on what ones are best for your location and when they are available.
Irrigation is still a necessity. The key is to water only where and when it's needed. Drip systems not only conserve water but also reduce time weeding because you are not watering the entire garden, only right where it's needed. Even a lawn sprinkler system can be made more efficient by adding a programmable timer to water early in the morning before the hot sun evaporates much of the spray. Watering longer, less frequently will not only save water but will encourage deeper roots thus creating a lawn that is more dense and crowds out weeds.
The most recent concept in gardening is waste efficient landscaping. This is a bold, wide encompassing step. The most visible result is a reduction in plant waste. Mowing your lawn more frequently, cutting less off at a time and just leaving the grass clippings on the lawn not only provides nutrients back to the soil it also reduces the amount of waste transported. It is true that more yard waste is being recycled. However, not all of the waste produced can be recycled. Even the waste that is recycled has to be transported, thus consuming fuel, and bagged, thus producing plastic. Good soil amending combined with applications of organic based fertilizers, which break down more slowly, not only reduces the amount of time spent pruning and feeding it also produces plants that grow slower and more evenly with less trimming waste. Healthy plants will require less insect and disease control again reducing the amount of time gardening and spraying but also reducing the amount of sprays and bottles produced as well as fuel transporting those bottles.
Suggesting all Californians rip out their entire landscape and replace with drought tolerant plants is unrealistic and counter productive. This would be depleting a resource we all could use more of: time. Pick a small portion of your yard, perhaps the least efficient area. If a large number of Californians reduce water consumption by even a small amount the end result would be amazing.
DROUGHT TOLERANT PLANTS AND TREES
TREES
African Sumac
Australian Willow
California Buckeye
California Pepper
Cedar
Crape Myrtle
Cypress
Elm
Eucalyptus
Evergreen Pear
Fruitless Mulberry
Goldenrain Tree
Magnolia
Oak
Olive
Palms
Pistachio
Poplar
Raywood Ash
Silk Oak
Silk Tree (Albizia)
Sycamore
MEDIUM TO LARGE SHRUBS
Blue Hibiscus
Bottlebrush
Cape Honeysuckle
Ceanothus
Cotoneaster
Hopseed Bush
Indian Hawthorn
Japanese Barberry
Manzanita
Oleander
Photinia
Pineapple Guava
Rockrose
Viburnum
Wax Leaf Privet
Xylosma
SMALL SHRUBS
Abelia
Heavenly Bamboo
Japanese Boxwood
Juniper
Wheeler's Dwarf' Pittosporum
VINES
Bougainvillea
Carolina Jasmine
Creeping Fig
Hall's Honeysuckle
Passion Vine
Pink Jasmine
Potato Vine
Star Jasmine
GROUNDCOVER
Gazania
Iceplant
Star Jasmine
Trailing African Daisy
Trailing Lantana
Trailing Rosemary
PERENNIALS
Aloe
Artemisia
Aster
Autumn Sage
Cranesbill
Daylily
Fleabane
Fortnight Lily
Gaillardia
Gloriosa Daisy
Lantana
Lavender
Lily-of-the-Nile
Limonium
Marguerite
Mexican Sage
Sedum
Society Garlic
Verbena
Wallflower
Yarrow