Daniel Gill, Merrill, Thomas A. | 4/19/2005 10:28:54 PM
It is most often done to annuals and perennials, but deadheading also is useful with some summer-flowering trees and shrubs.
There are a number of advantages to deadheading that make it worth the time and effort it involves.
For one thing, it improves the appearance of a plant tremendously. Plants that bloom over a long period often end up with an accumulation of unattractive dead flowers and seed pods mixed in with the newly opened blooms. This makes the plant look bad even with pretty flowers on it. If you keep the faded flowers pruned off the plant, it always looks fresh – as if it was just coming into bloom.
Removing the old flowers from many types of plants also will encourage them to bloom more and for a longer period. Annual plants, in particular, bloom for a time, set seed and then stop blooming and die. Regularly removing faded flowers prevents the plants from setting seed. As a result, annuals will respond by producing more flowers over a longer season in a continuing effort to set seed. Many perennials also will send up another flush of flowers if they are promptly deadheaded.
There are other advantages to preventing bedding plants, perennials and bulbs from setting seeds. Unless you intend to grow new plants from the seed produced, it is a wasted effort. Plants commit considerable resources to creating seeds. This effort could be redirected to growing more leaves, stems and roots – thus leading to a more vigorous plant and perhaps more flowers the next season. For annuals and perennials that self-seed, deadheading prevents unwanted seedlings from popping up all over the garden.
Depending on how the flowers are produced, deadheading may involve removing flowers on a single stem, faded clusters of flowers, faded flower spikes or individual faded flowers. For example, you remove a stem with gerbera daisies but remove faded clusters of flowers in yarrow, agapanthus or amaryllis. With snapdragons or veronica, deadheading involves removing flower spikes. But if they are large enough, individual faded flowers can be removed from a stalk or cluster containing numerous flowers – as with rudbeckia, daylily and stokesia. In this case, as individual flowers in a cluster open and fade, they are removed, but flower buds are left in place to bloom. Once all of the flowers have opened and finished, the entire stalk is removed.
When deadheading, always remove the flower stem that attaches the flower to the plant when you remove the flower. The idea is to remove any evidence that there was a flower at that location. Besides, the headless flower stems are unattractive.
If you miss removing the faded flower and a seed pod already has started to develop, go ahead and remove the seed pod. You may still help encourage the plant to bloom longer or prevent the plant from wasting energy on further development of the seeds.
On the other hand, if you want to collect seeds from a plant or if you want it to self-seed in your garden, you must allow at least some of the flowers to set seed. The best way to handle this situation is to deadhead early in the flowering season and then let some of the last flowers set seed.
While you are deadheading, take the opportunity to groom your plants by removing damaged, unattractive foliage and dead stems or branches. Not only is this healthier for the plants but it also keeps them looking their best.
It also is a good time to inspect your plants for developing insect or disease problems and to decide what kind of control, if any, is needed. And while you’re at it, notice if any plants need to be staked or supported after months of growth in the garden and attend to that as well.
There are a few summer-blooming trees and shrubs that can benefit from deadheading. Crape myrtles, vitex and oleander are more likely to produce a second flush of flowers after the first is finished if you are able to trim back the old flowers or developing seed pods. Make your cut just behind a faded cluster or flower spike.
There even are a few situations when perfectly good flowers are removed from plants. In the case of coleus and caladium, where the colorful foliage is the star, the flowers or flower spikes are removed to encourage production of more attractive foliage. Flower spikes of herbs, such as basil, parsley and cilantro, also are often removed to encourage continued production of flavorful leaves.
Once again, the plants that respond best to deadheading by extended flowering are annuals and perennials that bloom over a relatively long season and some summer-flowering trees and shrubs such as crape myrtle, vitex, rose and oleander.
Keep in mind, however, that deadheading will not extend the flowering time of shrubs such as azaleas or hydrangeas that bloom from a set number of buds. It also will not extended the flowering time ofr perennials that bloom over a relatively brief season. But it still can make them look more attractive and prevent them from wasting effort and energy on seed production.
Get It Growing is a weekly feature on home lawn and garden topics prepared by experts in the LSU AgCenter. For more information on such topics, contact your parish LSU AgCenter Extension office or visit our Web site at www.lsuagcenter.com. A wide range of publications and a variety of other resources are available.