Lilacs prefer well-drained neutral to alkaline soil in areas that provide abundant sunlight for at least six hours a day. Add a layer of compost to the plant each spring to fertilize the soil, followed by a layer of mulch to retain moisture. Water lilac during the summer when rainfall totals less than 1 inch per week. Spread lime and well-rotted manure around the base of the plant after blooming.
Lilacs need a lot of growing room; place plants between five to 15 feet apart depending on variety. Too little sunlight, soil that has been overfertilized and excessive pruning may keep lilacs from blooming. Use a handsaw to remove one or two older limbs after the plant blooms in spring to encourage healthier growth. Regular pruning is essential for maintaining healthy plants. Cut older, leggy stalks from the bottom of the plant and prune younger stalks back to approximately half their length.
Lilac trees are hardy shrubs that are easy to grow and can live for hundreds of years when properly maintained. Powdery mildew is one of the most common diseases to affect the lilac. Plant lilacs either in the spring or fall, although later plantings are often preferable. Container-grown plants are easy to transport from the nursery to the soil.