Most of your planting, especially of chaparral/scrubland shrubs and trees, should be done during the winter. Perennials, grasses, and riparian (water-loving) plants can be planted in the spring, though you will have more success planting during the cool, wet season. Gardeners in moderate, coastal areas can extend the planting season into the spring, though again working with our seasonal weather pattern is preferred.
Pay attention to new plants as they become established in your garden. Some will need supplemental water all year for about two years. Pinch back fast growing shrubs to encourage dense growth. This is particularly important for young sages (Salvia spp.). Excessive new growth can lead to weak structure, and the succulent growth is enjoyed by aphids. Prune and dispose of heavily infested stems. This problem usually resolves itself when ladybugs start to feast on the juicy aphids, and when the plant’s growth rate slows as summer approaches.
Cut back some spring and summer growing plants, such as coyote brush (Baccharis pilularis) and warm season grasses, deer grass (Muhlenbergia rigens). If you water and apply a dilute application of fertilizer these plants rebound quickly. Be conservative with the fertilizer to avoid excessive growth that requires pruning, and can be susceptible to stress from the summer heat and drought.
Many spring flowering shrubs, such as Ray Hartman wild lilac (Ceanothus ‘Ray Hartman’), can be pruned lightly after they bloom. New leaves grow on some of these plants above the flower stems. Prune the spent flower clusters to maintain a dense growth habit and eliminate these long bare stems.
Tidy up your garden. Remove weeds before they set seed. After you clean up weeds and spent wildflowers you can apply mulch to your garden to keep it neat and moderate soil temperatures. Inorganic mulch, such as decomposed granite, gravel, and rocks, is best suited for dry gardens with desert, chaparral, and scrub plants. Organic mulch is appropriate for woodland gardens.
Visit gardens, attend garden tours, chase the wildflowers and hike the San Gabriel Mountains to see the state’s remarkable flora in different settings. The most successful gardens take their clues from nature.