Q: Can I still prune down lilacs and early flowering shrubs this year?

• Matt from Poland

A: Yes, you can, but if you want all of your flowers next year — don’t do it!

Lilacs are a spring blooming shrub. Most spring blooming flowers form their flower buds from August to October. So, whatever stems you prune now will include those flower buds for spring of 2025! Your best bet is to wait until after the lilac blooms next spring, then selectively prune the shrub back to the height you want. In general, you prune plants just after they bloom (but there are exceptions)!

In general, pruning back for height should not be done all at once. In this case, you could cut back a few stems to begin the process. While this will reduce blooms, it will still give you some color in spring. Plan on cutting back no more than one-third of the stems this year, then continue the same practice next year.

Most traditional lilacs have multiple stems coming out of the ground. These are the types we get most questions about. When lilac shrubs get old, gardeners see fewer and fewer blooms. Thus, gardeners want to start pruning to regenerate the plant. In this scenario, pruning out three or four of the largest diameter stems is OK this time of year. Continue this practice in the spring each year. The younger stems will gain strength and bloom within a couple of years.

While early blooming shrubs are usually a no-no this time of year, it is OK to prune late summer blooming shrubs right now. Shrubs such as beautyberry and paniculata hydrangeas can be pruned during the fall season, or even in late winter before buds begin to break. Hydrangea arborescens is a plant which can be pruned down to about 6 inches high this time of year if you are looking for bigger, more uniform blooms. New stems will emerge and bloom by early June. This practice will result in strong stems and larger blooms. Not pruning Hydrangea arborescens will result in smaller blooms.

While there are general rules for pruning many shrubs in your landscape, you still need to do your homework. Do the basic research to be sure you are pruning at the correct time and that you are pruning the correct amount (not too much).

While you are out there pruning, remember to water your evergreens. It is of utmost importance to water them this year due to the drought. Continue to water them until the ground freezes, about 1 inch per week.

For more information on pruning lilacs, visit http://go.osu.edu/prunelilacs

For more information on when to prune flowering shrubs, visit http://go.osu.edu/prunetime

Eric Barrett is OSU Extension educator for agriculture and natural resources in Mahoning County. The plant and pest clinic is open Mondays and Thursdays from 9 a.m. to noon at the OSU Extension Office in Canfield. For more details visit http://go.osu.edu/mahoningclinic