full, I have been asked many times "Why doesn't my Lilac flower as good as before". The reason is usually the amount of light. Many plants get less light as the trees grow larger around them. Also Lilacs are plant in one direction light. This means one side flowers more than the other.
Moisture
aveage
Soil & Site
average, doesn't like soggy wet
Flowers
single pinkish, borne on a panicle
Fruit
beaked dehiscent capsule
Leaves
opposite, simple, glossy green leaves that can suffer from powdery mildew in the fall
Stems
raised lenticels
Dimensions
8-15 feet high by 1/2 to 3/4 spread, too large for use near the house, best used as specimen plants or in shrub borders, can be used on corner plantings as long as given 6-8 feet from the corner
Maintenance
Since Lilacs bloom on next season’s wood, prune after they are done blooming. There are many different ways to prune a Lilac. The most drastic is to cut them down to the ground. I have had ones sucker back and regrow while others that didn't make it using this method. You can cut out the old stems and let the new suckers fill in thinning them to the desired amount. On many old plants we have removed all the suckers and left a few of the old stalks. Pruning them up to bare base stems, turning the plant into a small tree. Drastic pruning may delay flowering a few years.
Native Site
Lilac is native to Europe and has been in cultivation since the 16th century