Connecticut Garden Journal: How To Prune Shrubs | Connecticut Public Radio

Connecticut Garden Journal: How To Prune Shrubs

Feb 9, 2017

Everyone loves flowering shrubs, such as lilacs and rhododendrons, but you may be wondering, how should I prune this thing? Pruning reduces the size and shape of your shrub, but you have to know when and how you do it.

The first task is to know if your shrub flowers on new or old wood. It's simple. Remember when your shrub blooms. If it flowers before July 1, chances are it's flowering on old wood. The flower buds formed last summer.

Lilacs, azalea, rhododendron, and weigela are some of these shrubs that need to be pruned right after flowering. If you prune too late, you'll remove the flowers for next year.

If it's flowering after July 1, it's probably blooming on new wood that started growing this spring. Shrubs, like clethra, butterfly bush, and rose of Sharon, should be pruned in late winter to stimulate more new growth and flowering.

Use "thinning out cuts" when pruning to reduce the shrub size. Thinning out is when you prune individual branches back to the ground or to a large side branch. This type of pruning will keep the natural shape of the shrub, open it up for more flowering and keep the size in bounds.

Shearing or "heading back cuts" just turns your forsythia, rhododendron, or spirea into a foolish looking box or ball that doesn't flower well.

Some shrubs, such as lilac, forsythia, and spirea, can be cut severely and will still eventually flower. Cut them back to a few feet off the ground or even to the ground. It will take a few years, but they will recover to start flowering.

Next week on the Connecticut Garden Journal, I'll be talking about unusual radishes. Until then, I'll be seeing you in the garden.