I think we’ve all been there before–loppers in hand, a shrub in front of us, questioning when and how to prune the darn thing! To find the answers, spend a few seasons learning when your shrubs bloom and their purpose in your landscape.
A shrub in bloom is not only a beautiful sight but a great key to understanding whether it is old wood flowering or new wood flowering.
Old wood flowering shrubs typically flower in the spring. These flower buds are set on last year’s growth and form during the summer and fall months. You should prune these shrubs within 4-6 weeks after flowering. Missing this window could mean cutting off all of your buds and missing out on next year’s flowers! A few old wood shrubs are forsythia, mock orange, and spring-blooming azaleas and roses.
New wood flowering shrubs typically flower in summer. These flower buds are set on the current season’s growth and form during the spring. It’s best to prune these in late winter, just before they break dormancy. Some new wood shrubs are butterfly bush, beautyberry, and chaste tree.
As for how to prune a shrub, you should always consider plant health, landscape purpose, and appearance. Keep in mind that pruning cannot replace choosing the right plant for the right place! Consider mature size and site requirements before choosing a plant; otherwise, you may get stuck pruning multiple times in a year to make it work in an unsuitable site!
For plant health, you should remove crossing limbs in addition to the three Ds –dead, diseased, and dying limbs. Removing redundant branches near the center of the shrub open it up to air circulation and sunlight but maintains the shape of the plant.
For landscape use, you may choose to hedge your shrubs or stimulate flower and fruit set. For hedges, prune yearly down to your desired height and shape. For flowers and fruits, thin out non-fruiting branches every few years. Remove weak and downward branches as they will not produce much fruit, if any at all. Thin dense branches as they can hinder fruit size.
Make sure your cuts are clean and go back to a larger branch or trunk. Angle cuts ¼” above an outward- facing bud. Cutting too high up can leave excess stem material that will rot and cutting too low will nick the bud and damage it.
So before you reach for your loppers, spend time with your landscape to see what you have and how you can make it better!
Selena McKoy is Horticulture Agent for North Carolina Cooperative Extension in Harnett County.