You guessed it -- the California lilac (Ceanothus spp.) is native to California. Known also as blue blossom or mountain lilac, it is perfect for the gardener who tends to neglect the garden a bit. However, to ensure that your California lilac thrives, give it some care and attention, especially in the first growing season and during hot weather. Then enjoy its annual spring and summer display of colorful flowers for years to come. Most California lilacs grow well in U.S. Department of Agriculture Plant Hardiness Zones 8 through 10.
Water a California lilac one or two times a week with 1 inch of water for its first growing season. For more drought-tolerant varieties, such as Ceanothus thyrsiflorus, gradually reduce how frequently you water it during the second year; in subsequent years, water these varieties once every three or four weeks. Water other California lilacs, such as Ceanothus maritimus, about once a week, especially during hot weather.
Clip off blooms after they fade to keep the shrub tidy. Cut back new growth to healthy leaf sets while it is actively growing to control the shrub's size. Do not cut branches that are more than 1 inch in diameter.
Fertilize California lilac every spring just as the leaf buds begin to swell. Use an all-purpose fertilizer, such as 10-10-10. Apply no more than the amount specified by the manufacturer, sprinkling it evenly under the shrub’s canopy, then water in the fertilizer with 1 inch of water.
Examine your shrub occasionally, looking for signs of insects and their damage, such as aphids on the underside of the leaves or browning leaf tips. Prune affected branches in small infestations to a set of healthy leaves and discard. Treat heavier infestations with an appropriate insecticide, such as insecticidal soap.
Things You Will Need
- Garden hose
- Pruning shears
- California lilacs do not like wet feet or standing water, so plant in soil that drains well.
- If your soil is rich in organic matter and your California lilac grows well without it, do not fertilize.