The Best Way To Cut Back Perennials Safely For Healthy Plants All Year Long

Looking for a way to improve your perennials' appearance, keep them blooming, and boost their health? Cutting them back can accomplish those goals and more. While several pruning techniques are available for removing parts of plants for various purposes — deadheading to remove flowers that have finished blooming, disbudding to detach side buds, and pinching to maintain compactness and control bloom time — cutting back your perennials involves cutting off the plant's entire top to ground or near-ground level to promote new growth. Use a sharp knife or shears to make clean cuts down to the base of dormant growth. Afterward, apply a light mulch treatment to the plant. Your perennial garden should thrive with thoughtful timing, technique, and your commitment to keep your perennials blooming longer.

If you want new foliage, need to control self-seeding, or seek to trim messy or out-of-control plants, cutting back is a little like deadheading on steroids. Of course, you'll also want to remove any diseased or decayed plant material to protect the health of your garden as part of cleaning up your garden at the end of summer. Trimming and tidying up not only improves their appearance but can also extend the blooming period for certain varieties that flower repeatedly. Importantly, cutting back can prolong the flowering of some perennials with multiple repeat blooms. In some cases, deadheading your flowering perennials is enough to produce more blooms, so get to know the perennials you should deadhead for blooms that keep coming. 

Keep a few cautions in mind when you cut back perennials. As you remove a significant portion of a perennial, don't cut into its basal rosette area– the point at which the leaves grow in a circle around the base. Check for signs of new growth in the center, indicating the plant will bounce back easily, and keep in mind that heavier pruning often coincides with a longer recovery period. You may want to limit or postpone your efforts at the end of the growing season to leave stems, seedheads, and habitat areas for wildlife. 

Consider cutting back your perennials in the fall after the end of the growing season, in spring before the growing season, and, if needed, mid-summer for bloom proliferation. Beebalm (Monarda), blanket flower (Gaillardia), catmint (Nepeta), and columbine (Aquilegia) are a few of the perennials that experts suggest be cut back in the fall. Wait for plants to go dormant or after one or more hard frosts. Spring is recommended for amsonia (Amsonia hubrichtii), aster, astilbe, black-eyed Susan (Rudbeckia hirta), and coneflower (Echinacea), among others. It's a good idea to research any plant before you begin for specific guidance on needs and best practices for each perennial. Decide whether you'd rather do a comprehensive fall clean-up so you have less to do in the spring or leave some of the mess for wildlife but have more tidying awaiting you in spring.