Perennial Cutback

So, your salvias and catmint have put on their spring show. Now what? Do you just let them sit there all scruffy for the rest of the season or do you ask them to step up their game? At Groovy Plants Ranch, we’ve learned some tricks to bring new life and even new blooms to many of your favorite perennials. 

Light Sheer for Early Bloomers

Light sheering will encourage a second round of blooms. When spring perennials like salvia are finished flowering, we take our pruning shears and cut back spent blooms. While some gardeners meticulously deadhead each individual flower, we prefer this quicker method lightly sheering the top few inches of the plant including both flowers and a few leaves. The sheering not only gives perennials a tidier look, but it also encourages plants to direct more energy toward root and shoot development and often results in a second round of blooms. Besides salvia, try the technique on other perennials like Shasta daisies, phlox, gaillardia, coreopsis, campanula, lady’s mantle, monarda and dianthus.

Hard Cut After Blooming

A hard cut is another pruning technique that works well on perennials like catmint. You’ll know it’s time to prune them when they start to flop in mid-summer. We just take our hand pruners, grab handfuls of stems and cut them back to an inch from the ground. Other good candidates for a hard cut include perennial geraniums and artemisia. Jared’s even known to take the lawnmower to his spiderworts, and theses tough perennials surprisingly rebound with another round of blooms.

Stem Cuts for Re-Blooming

Coneflowers and black-eyed Susans are prime candidates for cutbacks after blooming. Just remove the entire stem all the way to the base of the plant. The plant will send up new shoots for a second round of blooms.

Chelsea Chop for Control Growth or Delayed Blooms

Some perennials like amsonia, asters and baptisia benefit from a late-spring pruning to control their shape and delay or extend bloom time. In England, it’s called the “Chelsea Chop” after the famous Chelsea Flower Show that traditionally takes place in late May when the pruning technique works best. 

It may sound crazy but cutting back certain perennials like sedums can help improve their shape and even extend their bloom time. To do the cut back, take a pair of hand pruners or hedge sheers and cut back the top third or half of the plant. Try experimenting with pruning different parts. Some like to cut back just the front part of the plant (e.g., monarda), while others like to cut back the entire plant (e.g., goldenrod or helianthus). After pruning, make sure to give the plants a thorough watering and some fertilizer to help them rebound.

The pruning stimulates plants to produce more side shoots and eventual flowers, so count on more blooms, a longer bloom time, a more compact shape and less flop later in the season. 

For more information, check out this video demonstrating the “Chelsea Chop” at Beth Chatto’s award-winning gardens in Essex, England.

Prune Like a Pro