Nina Koziol is a contributing writer for State-by-State Gardening magazines.

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Deadheading Details
by Nina Koziol    

A little snip here and there can prolong your flower display and keep your garden from a midsummer slump.


If only all our perennials performed like blanket flower (Gaillardia). It’s one plant that’s flush with flowers, burgeoning buds and attractive globe-shaped seed heads from early summer until frost. Alas, that’s not the case for most perennials. So the next time you walk through your yard admiring the blooms, bring along a pair of garden shears and a pail so you can deadhead the finished flowers. “Deadheading” simply means removing dead or spent blossoms.



Why Deadhead?

Once its flowers have finished blooming, a plant has one goal: to reproduce itself, so its energy goes into seed formation. Perennials typically enter dormancy after their flowers produce seeds, while annuals die once the flowers go to seed. By snipping off spent flowers, you encourage many perennials, annuals and roses to continue flowering. In the case of some, such as black-eyed Susan, butterfly bush (Buddleia), peonies, hostas and daylilies, deadheading can improve the plant’s overall appearance. (A peony covered with white mushy flowers that look like used tissues isn’t exactly eye candy.) Removing spent flowers also helps prevent some perennials, like ornamental onions, lychnis or helianthus, from seeding themselves around the garden and becoming a nuisance.

New gardeners are often leery about where to snip, but it’s not difficult and you’re not going to harm the plant. Think of it as a little haircut. For perennials such as Shasta daisies, phlox and coneflowers, cut off the stem that holds the spent flower. Follow the stem down to where it meets the first set of leaves and make the cut right above them. You can do the same for annuals such as cosmos, zinnias, salvia and the tall Verbena bonariensis. In any case, cut at least an inch of the stem below the flower so that the ovary, which contains the immature seeds, is removed.

Rose growers often recommend cutting the stem below the spent rose to the point where you reach the first set of five leaves. This is where the plant has the best chance of developing a strong, new, flower-bearing stem.

After butterfly bushes provide their first big flush of flowers, usually in June, the plants continue to produce smaller blossoms. Keep removing the dried flowers and the bushes will bloom until the first autumn frost. Remove as many spent blooms as possible or the plant will continue trying to produce more seeds.

Most deadheading involves removing individual flowers, but with threadleaf coreopsis, just shear off the top third of the plant.

It’s easy to pinch off a single daylily flower. Seen here: ‘Strutters Ball’. Photos Courtesy of Bailey Nurseries.

Daylilies with heavily branched stems of small flowers shed the spent blossoms on their own, which keeps the plants reasonably attractive. But daylilies with larger, more noticeable flowers need a daily tweaking. As a rule, the larger and more opulent the flower, the less attractive it looks once it peters out. You can pinch off the spent daylilies with your fingers.

Coreopsis, especially the threadleaf varieties, produce a great flush of flowers that lasts for several weeks in early summer. When they’ve passed their prime, the easiest way to deadhead the stems is to use hand or hedge shears to trim about one-third off the top of the plant all at once. Shearing also works on perennial salvias and on some annuals like petunias and small-flowered plants like sweet alyssum. Cut back to just above the newest, youngest growth. This also rejuvenates plants that are spindly. Petunias in hanging baskets can be trimmed back to the basket’s rim. Most of these plants typically take about two to three weeks to produce new flowering stems.

There are some plants, such as foxgloves and poppies, that don’t warrant deadheading because they have a limited bloom period and produce few additional stems. Skip deadheading altogether on baptisia, sedum, Joe-Pye weed, ‘Herbstonne’ rudbeckia, liatris, Siberian iris and ornamental grasses, all of which produce beautiful seed heads that provide fall and winter interest. And if you want your coneflowers and black-eyed Susans to feed the birds during the winter, stop deadheading them by early September and let the plants do their thing.

Fear not the nip and tuck of deadheading. You will rarely do permanent damage to any plant. Worst case, you might nip off a flower bud by mistake. Meanwhile, your garden will look much tidier and healthier.


Posted: 11/02/11   RSS | Print


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