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 are shaded as the trees grow larger around them and also many Lilacs are plant in one direction light. This means one side flowers more than the other.
Moisture
average
Soil & Site
average, avoid wet and soggy
Flowers
panicles of single blue florets, fragrant
Fruit
seeds in loose clusters of brown beaked dehiscent capsules
Leaves
simple, green leaves, may suffer from powdery mildew in the fall, best planted where it has good air circulation
Stems
raised lenticels on the stems
Dimensions
4-5+ by 6+ feet (HS)
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