The lilac bush, a deciduous perennial shrub, grows natively on rocky hillsides in southeastern Europe. Hardy in zones 2 through 5 in the United States, lilac requires cold winters to induce blooming and cannot thrive in the warmest areas of the country. The slow-growing shrub takes a long time to become established and may not flower for the first few years after planting. Without proper care, lilac bush may never flower at all. Gardeners value the shrub, however, for its fragrant flowers that appear in spring each year after the first bloom.
Plant lilac bushes in a location that receives six to eight hours of direct sunlight each day. Spread a 3-inch layer of aged manure over the planting site and use a garden tiller to amend the soil. Space lilac bushes 10 to 15 feet apart for single displays or 5 to 8 feet apart for hedges.
Water once per week during the first year of growth to help establish the root system. Reduce thereafter to once every 10 days, but only during periods of drought. Apply water directly to the soil to minimize the risk of disease.
Feed twice per year, once in early spring before active growth resumes and again immediately after blooming. Use a balanced 10-10-10 NPK fertilizer to provide the necessary nutrients for growth and flowering. Apply according to the manufacturer's directions.
Remove faded flowers as often as possible to lengthen the blooming period. Pinch off the flowers as close to their point of origin, or the area where they meet the stems, as possible and new blossoms will replace them shortly thereafter.
Prune your lilac bush only when it becomes leggy with excessive bare growth near the base of the plant. Use pruning shears to remove 1/3 of the oldest stems at ground level each year for three consecutive years to fully rejuvenate the shrub.