Lilacs can be used as freestanding shrubs, hedges or trees. Lilac plants grow up to 20 feet tall, providing good shade in your yard. With deep roots, lilacs prefer to be planted in raised elevations, on hillsides, or on level ground with good drainage. While there isn't a magic solution to making a lilac grow faster, good maintenance habits and a focus on pruning, mulching, and fertilizing will give the plant everything it needs to produce vigorous growth.
Plant lilac varieties that grow fast. Late blooming hybrids like "Agnes Smith" and "Miss Canada" grow quickly, getting up to 25 feet or taller. They bloom later than other lilac types. Agnes Smith has white flowers and Miss Canada blossoms are rose-pink. Syringa chinensis also grows fast and blooms often, with purple flowers.
Spread mulch around lilac plants to keep weeds from stealing nutrients from the plants. A layer of 2 to 3 inches of pine bark will stabilize the temperature of the roots and help retain soil moisture.
Prune the plants to encourage blooming and growth. Trim the plant annually, right after it finishes blooming, to improve vigor. Remove weak branches until you have a clump of seven to 10 stems of varying ages.
Thin out top growth to let sunlight into the center of the lilac. New buds will form and the plant will grow faster. Remove less vigorous stems and those that are crossing or rubbing against each other. Cut off flowers after they die to make the bush look better.
Increase growth with a fertilizer in early spring or mid October. Apply 1/2 lb. of 5-10-10 fertilizer per 25 square feet. Spread the fertilizer around the base of the lilac, and water it in.