Time to Maintain: Deadhead Your Annuals and Perennials

Keep your summer garden attractive and blooming into fall by regularly deadheading! What is deadheading? When and why is it necessary? The NCSU Extension Gardener Handbook explains deadheading as follows:

Deadheading is the removal of dead or faded flowers and seed pods. When annuals and perennials expend energy to produce seeds after the flower fades, flower production often decreases. To maintain vigorous growth and assure neatness, remove spent flowers and seed pods.

Although this step is not necessary for all flowers, it is a good practice with ageratum (Ageratum houstonianum), calendula (Calendula officinalis), celosia (Celosia argentea var. cristata), coleus (Coleus ×hybridus), cosmos (Cosmos bipinnatus), geraniums (Pelargonium ×hortorum), marigolds (Tagetes erecta, T. patula), scabiosa (Scabiosa atropurpurea), salvia (Salvia argentea), black-eyed Susan (Rudbeckia fulgida), and zinnias (Zinnia elegans). Check plants weekly. Many modern cultivars are self-cleaning; their spent flowers drop off quickly. Some cultivars are sterile and do not produce seeds.

Different plants; different techniques
Deadheading is not a complicated gardening task, but it helps to know when to apply different techniques. In general, use your fingers to snap off the flower head, or pruners to clip off the spent blossom just above the first healthy leaves on the stem—the classic technique for marigolds and zinnias. For bushy plants that flower on tall stalks—such as rudbeckia and daisies—remove the topmost flower down to where a lateral flower comes out of the stem. As each lateral flower blooms, keep cutting the main stem back to the next leaf bud.

Pinch faded blossoms of tall, spiky flowers—such as delphiniums, cardinal flower, and gladiolas—from the bottom up. Cut the entire stalk to the ground when it is nearly barren of flowers.

Daylilies produce several flowers at the end of their stalks. Pinch off each blossom as it fades and then cut the stalk to its base within the foliage clump. Mounding plants—such as petunias, catmint, and cranesbill—may benefit from mid- to late-summer shearing to encourage new growth and a bushier appearance.

Some plants don’t need deadheading at all—think impatiens, begonias, and vinca. Their blossoms fade and drop off naturally. For plants that will not rebloom—such as peonies, astilbe, most iris, and hostas—deadheading keeps the garden looking tidy.

A wildlife-friendly, winter garden
As fall approaches, consider allowing your summer flowers to go to seed. Seeds, seed pods, and hips provide birds a needed food source in winter. Perennial stalks, left standing, provide protective groundcover for wildlife and offer winter garden interest. If your garden space allows, take advantage of prolific reseeding from plants like rudbeckia, Echinacea, columbine, verbena, cosmos, and California poppies. Come summer, you will enjoy a host of blossoms from these new plant volunteers. 

References
NCSU Extension Gardener Handbook, Chapter VII, “Maintenance of Annuals and Perennials.” https://content.ces.ncsu.edu/extension-gardener-handbook/10-herbaceous-ornamentals#staking

Fine Gardening magazine, Issue 92, “Off with Their Heads,” offers an extensive list of perennials that may rebloom after deadheading, as well as those that do not but benefit in appearance from deadheading.  http://www.finegardening.com/their-heads-deadheading-perennials

Article written by Beth Leonard, Extension Master Gardener^SM Volunteer.