Lilacs are members of the Syringa genus and are often grown as individual bushes or grown in rows to form a hedge or border. Lilacs bloom a brilliant display of small flowers that grow in clusters at the end of a branch or stem. Plant lilacs in full sun and in soil that is well-draining and has a pH level between 6.5 and 7.0. After planting your lilacs, in order for them to bloom to their fullest potential each year and for them to look lush, you must properly care for them.
Spread a 2-inch layer of mulch, such as pine bar, around your lilacs. This will help keep weeds at bay, maintain more even soil temperatures and help retain moisture.
Cut off blooms when they are done flowering. Cut them back to the first set of leaves beneath the blooms. This practice will help encourage more blooms and help prevent the lilacs from spending its energy on making seeds. It will instead save and use its energy for next year's blooms.
Prune back your lilac when the bottom branches lack flowering stems and your bush looks "woody." Do this after it is finished blooming. Cut off one-third of the stems right at ground level. Choose the branches that are the oldest. Do this for three years and your bush should grow to be full and lush again.
Fertilize your lilacs with a balanced fertilizer labeled (e.g., 10-10-10). Do this in the early spring when new growth begins and when the bushes are finished blooming. Read the label for application and dosing instructions since each kind of fertilizer is different. Always water your lilacs and any plants well after fertilizing.
Watch out for disease and insect damage, such as those from lilac border insects or powdery mildew. If you notice holes, a dusty film or spots on your leaves, take a sample to your local nursery or county extension office for diagnosis and treatment plan. Most likely you must apply a pesticide or insecticide.