Dark Knight Lilac has single, dark purple flowers. Because of its minimum chill requirements, it is a good choice where winters are mild. They are fairly low-maintenance plants, grow best in full sun and can handle slight but not full shade. Soil that is rich in organic matter with a pH that is slightly acidic to slightly alkaline is best. If pruning is required, do so immediately after the plant has flowered. Removing faded flower panicles from lilac plants before they go to seed will achieve better blooms the following year. Lilacs are susceptible to powdery mildew.  Good air circulation is key to preventing powdery mildew and other diseases.