Each method has its advantages and disadvantages in time and degree of difficulty. The easiest methods for the home gardener are root sprouts and layering, using a named variety. Growing lilacs from seed is not recommended. Because most lilacs are hybrids, plants grown from seed will not produce plants just like the parent plant. Root Sprouts Root sprouts provide the simplest and most usual way of propagating the common lilac.
Some lilacs send out suckers near the base of the plant.
Dig up these new sprouts in the fall and transplant them elsewhere in the garden or in a nursery. They often develop into satisfactory plants in about 3 years. This method, however, will not be satisfactory for grafted plants, because the suckers will not be like the tops of the plants. Look for a graft union near the soil line to determine if a plant is grafted. Layering Layering is an easy, but slow process for increasing lilac plants in the home garden.