Pruning common lilacs

Asked September 21, 2015, 11:55 AM EDT

We planted two lilacs a year ago. Right now they are about 5' tall. Most of the stalks are bare all the way up to about 6" from the top where they have leaves. Is this normal? Do we prune them back after flowering next year and how far down? Are stalks that have no leaves dead and should be removed?


Denver County Colorado trees and shrubs pruning shrubs lilacs

1 Response

Hi there!

I'm going to assume that you have regular lilacs, not dwarf lilacs. To answer your first question, bare stems are not normal, but there has been so much rain this spring, the lower leaves may have gotten powdery mildew and fallen off. This fall, clean up the fallen leaves so less fungus has a chance to overwinter. You will likely not have bare branches next year, but if you experience this once again, please contact us.

You should prune after flowering next year. It is recommended that multi-stemmed shrubs like lilacs be 'renewal pruned', not sheared, but it depends on how tall you want them to grow. If you want to keep them a certain height, they can be sheared, but don't take more than 20 percent of the plant.

If you choose instead to renewal prune, take out the oldest stems. That will induce new growth. However, your plants may not be old enough to warrant renewal pruning.

Hope this helps. Have a great fall.