CULTURE: Plant most varieties in full sun; only S. laciniata in our list will perform well in partial shade. All Lilacs require well-drained soil with pH close to neutral. Add lime if your soil is extremely acid. S. vulgaris varieties are prone to powdery mildew, which generally appears in late summer. Mildew disfigures the leaves to varying degrees, but seems to have little effect on the vigor of the plant. Immature lilacs produce flowers with lighter coloration; it may take 4-6 years for their true color to show. PRUNING: Prune as necessary after bloom in spring.