Dead-Heading Techniques

Perennials bloom for a few weeks each season but gardeners have learned to extend blooming periods by dead-heading. Dead-heading is the removal of spent, mature flowers that are turning brown or losing their petals. If left to nature most of these spent flowers will develop seeds. When they ripen the plant starts to decline in preparation for dormancy and next season’s growth. Deadheading interrupts this natural cycle encouraging plants to continue to produce new buds, prolonging the blooming period thus more flowers in your garden. Dead-heading prolongs blooming, promotes a second flush of flowers, discourages disease, improves the plants appearance and prevents seed formation which is good for reining in vigorous self-seeders such as lady’s mantle.

Dead-heading techniques vary depending on the growth habit of each plant.  The spent flowers of most perennials can be pruned back to a new bud or leaf axil, which appears lower down the stem. Bellflowers, columbines, coneflowers, phlox and Shasta daisies can be dead-headed by cutting off the spent flowers stem about half a centimeter above the next flower bud or where the next pair of leaves joins the stem of the plant if there are no buds. The blooms of other types of perennials including coral bells, thrift and torch lilies grow at the top of long stems and these should be cut back right down to the base of the plant.

dead-heading techniques harmony gardens ottawaDead-heading by shearing:  Many annuals and perennials will take the rather drastic treatment of shearing.  Good candidates are low-growing rock garden plants such as aubretia, trailing lobelia, fine-textured plants such as coreopsis; plants that send out long-flowering shoots such as hardy geraniums; and vigorous growers such as snow-in-summer. Basket-of-gold, candytuft, sweet alyssum, rock soapwort, spike speedwell, and bachelor buttons all do well with shearing. Using clean, sharp garden shears clip away all spent blossoms and leggy, untidy growth. Shearing refreshes annuals such as petunias and nasturtiums that tend to get straggly.

Dead-heading individual flowers or stems: Perennials such as irises and daylilies generally have clusters of flowers at the top of the stems.  Using fine pointed scissors or pruners snip individual blooms as they fade one by one including the swelling at the base of the flower where seeds would form. Be careful not to disturb new buds below. Once the last buds have opened cut the stem off at the base. Regularly snip off the dead flowers of annuals such as marigolds, verbena and pansies to maintain blooming.

Piece by piece dead-heading techniques required for plants with tall spikes of blooms such as tall garden phlox, foxgloves, delphiniums, monarda and Culver’s root which produce secondary flowering shoots lower on the stem. Cut off the main cluster once it is bloomed down to secondary shoot.  Once all the side shoots are done, take out the stem at the base. Cut back the finished stems of plants such as peonies, dahlias and lupins to a leaf node so the cut is less visible.

Stem by stem dead-heading for plants such as bleeding hearts, hostas, heucheras, liatris, bergenias, red hot pokers and many euphorbias just snip off the spent flowering stems right at the base of the plant.