When do you cut back lilacs?

Question

I was told some time ago that you need to cut back lilacs after blooming. Since mine are done I wonder when I should do that.
Do next years grow on new growth?Thanks

Answer 1

You need to get to them rather quickly since they set their flowers for next year in July. Any tip pruning after that removes the flower buds.

Remember to also prune down at ground level, moving excess sprouts and older growth. Othewise the plant can get out of bounds.

Answer 2

You should cut them just as the blooms are finished. If you still have the dried up blooms on your bush - you can still go ahead and trim it now. But don't wait much longer.

Answer 3

.............Harvard University........................
http://www.arboretum.harvard.edu/plants/lilac_care.html
They know more than the average person on Yahoo!
Most plants and shrubs need to be cut back right after blooming. Some plants need to be cut back a minimum amount of time after blooming..........ie; irises /5 weeks after blooming.