Answer: The common lilac (Syringa vulgaris) will grow in your area, but may not bloom faithfully for you. Lilacs need a pronounced period of cold weather to bloom best, and yours is a mild winter area. For best performance your should grow one of the Descanso Hybrids that have been developed to perform especially well in Southern California. "Lavender Lady", "Chiffon", and "Blue Skies" would all be good bets for your garden. If you've chosen one of the Descanso Hybrids that were specifically developed for Southern California, your lilac may only need a little more TLC to bush out and begin to bloom for you. Lilacs prefer to grow in full sunshine, in average soil, with regular watering during spring and summer. Once established, lilacs grow lush and full and may need annual pruning to keep them within bounds. Prune after flowering to allow the development of buds for next year's bloom.
I'd feed the lilac early next spring (10-20-20) and keep the soil moderately moist but not soggy wet. It should be mature enough to bloom for you next spring.
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