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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Deadheading Herbaceous Ornamentals and Roses

This article was published originally on 6/16/2003

The removal of spent flowers (deadheading) on annuals, perennials, and roses is an important gardening chore. Deadheading improves the appearance of many plants, encourages the formation of additional blooms, and prevents the development of unwanted fruits or seed pods. Annuals

Pinch off the faded flowers on annuals, such as petunias, geraniums, marigolds, zinnias, cosmos, pansies, and snapdragons, on a regular basis to prevent seed formation and promote flowering. Impatiens and a few other annuals are self-cleaning and don t require deadheading. Perennials

The flowering period of many perennials, such as coreopsis, garden phlox, shasta daisy, and yarrow, can be prolonged by deadheading. Delphiniums often bloom a second time in late summer if the initial flower stalks are cut back after flowering. The removal of spent flowers on peonies and bearded irises promotes plant vigor by preventing the formation of seed pods. Deadheading also prevents the self-seeding of golden marguerite, yarrows, and other potentially invasive perennials. Roses

Modern roses, such as hybrid teas, grandifloras, and floribundas, should be deadheaded to conserve the plant s energy and encourage repeat bloom. During the first growing season, remove the faded flowers above the uppermost 3-leaflet leaf. Removing a larger amount of foliage reduces the young plant s ability to manufacture food and may slow its growth. When deadheading established roses, the stem may be cut back to a 5-leaflet leaf. Retain at least two 5-leaflet leaves on each shoot. Using hand shears, cut about 1/4 inch above the leaf with the cut made parallel to the angle of the leaf. Stop deadheading hybrid teas, grandifloras, and floribundas in late summer (late August or September). The development of rose hips (fruits) slows plant growth and helps prepare the plants for winter.

There is usually no need to deadhead old-fashioned, shrub roses as many are one-time bloomers. Plus, the hips of some are quite attractive.



This article originally appeared in the 6/16/2003 issue.

Year of Publication: 
2003
Issue: 
IC-489(14) -- June 16, 2003