Summer is upon us, and the perennials are growing beautifully. But recently I noticed some of mine were getting a little leggy, especially my Black-Eyed Susans. One of the most common questions gardeners ask this time of year is:
“Should I prune now?”
The answer is yes.
Many perennials, including Coreopsis, Salvia, Black-Eyed Susan, and Blanket Flower, put on a burst of growth and bloom during spring. As the season progresses, however, they can begin to stretch, flop, and look a little tired.
I usually wait until the first flush of flowers starts to fade before giving them a trim. How much you cut back depends on the plant and its growth habit. Sometimes you can cut them back to just 3–4 inches tall. Other times, it’s best to prune back to a point where you can see healthy new branches forming. Within a few weeks, most will respond with fresh growth and a new round of blooms.
Asters are another perennial that benefits from an early summer haircut. Here at the nursery, we grow Willow Leaf Aster, a native fall-blooming perennial that provides a valuable late-season nectar source for bees and other pollinators. Left alone, it can easily reach 3–4 feet tall by late summer.
I routinely prune mine in June to encourage a shorter, bushier plant with more flowers when it blooms in fall. This type of pruning is often called the Chelsea Chop, a gardening technique named after the Chelsea Flower Show in England. By cutting back certain perennials in late spring or early summer, gardeners can encourage denser growth, stronger stems, and often enjoy a longer bloom season.
This early summer pruning can do wonders for many perennials. Not only does it improve their appearance, but it often extends flowering well into summer and fall. If needed, you can give them another light trim in late summer, but keep that pruning minimal. At that point, you’re simply encouraging a little fresh growth and a few additional blooms before cooler weather arrives.
Before You Grab the Pruners
Not every plant benefits from summer pruning.
Many flowering shrubs, including some hydrangeas, as well as many fruiting trees and shrubs, are already producing the growth that will become next year’s flowers and fruit. Pruning these plants too heavily after June can reduce or even eliminate blooms and harvests the following season.
As a general rule, summer pruning works best on herbaceous perennials such as Coreopsis, Salvia, Black-Eyed Susan, Blanket Flower, and Aster. Before pruning shrubs, trees, or fruiting plants, it’s always worth learning when they set their flower buds and fruiting wood.
When in doubt, remember this simple rule: if a plant blooms on old wood, late pruning may remove next year’s flowers.
Keep in mind that these recommendations are based on gardening conditions here in Southeast Georgia. Gardeners in cooler climates may need to adjust their timing to fit their growing season.
And one final tip—don’t throw those spent flowers away! Many can be dried, and the seeds can be collected and scattered throughout the garden. You may be rewarded with even more plants next season.
Nature always wins. As gardeners, we simply learn to work with it.
— Blackcreek Nursery
