22 May 2007
Virginia Cooperative Extension, Charlottesville/Albemarle County Office
460 Stagecoach Road, Charlottesville, Virginia 22902
phone: 434.872.4580 fax: 434.872.4578
Now that spring plants are in bloom it is a good idea to consider deadheading. I am not referring to the buying of Ratdog tickets or cuing up a favorite recording. Deadheading in the garden is the removal of spent flower heads to give you more flowers to enjoy. Aside from more flowers, deadheading can also improve the appearance of a plant by simple neatness and by encouraging more vegetative and root growth.
If you think about it from the plant perspective flowering is the means to producing seed and reproduction of the species. Once seed is produced many plants stop producing flowers since their main reason for living is complete. After the removal of the spent flowers or seed heads by deadheading, plants revert to the reproductive mode and start flowering again.
Sometimes we want plants to produce seed to provide food for birds such as sunflowers and coneflowers or so they or we can propagate more of the same as with things like alyssum, nicotiana, cleome, larkspur, poppies, and dandelions. Other times the seed head is interesting enough to leave it on for aesthetic reasons. Much of the time we are not planning to harvest this seed.
The seeds that were silent all burst into bloom and decay
There are some plants that do not rebloom with deadheading so it is a good idea to do your homework before you expend the energy if that is your goal. Also there is more than one way to deadhead. Some plants should be cut back to a lateral flower, bud, or leaf (e.g. Artemisia, Delphinium, Iris) whereas some should be cut back to the ground (e.g. Crocosmia Lucifer, Hosta, Liriope). There are lists available on the internet and in some gardening books or you can ask your local Extension office about a specific plant.
If a plant flowers all along a stalk gradually and sequentially rather than all at once it is good to deadhead once the halfway blooming point has been reached. If this stalk has new buds next to old, then the individual flowers should be removed rather than taking the whole stalk. Try not to remove foliage with the flowers if you are selectively deadheading.
If your habit is to be out in your garden each day, keep deadheading in your mind and your pruners close at hand so you can keep up with this task and not let it become overwhelming from neglect. Consider using all those leaves, flowers, and stems resulting from trimming and deadheading as compost, assuming they are free of disease and insects.
Maybe it was the Roses
For roses deadheading is the removal of spent flowers so that hips, the rose fruit, do not form. This maximizes rebloom on repeat-flowering roses by diverting the energy normally used for hip development into new flowers and cane growth. If a rose is female-sterile, deadheading occurs naturally as spent flowers drop off the plant.
The only reasons for deadheading a one-time-blooming rose are to give the plant a cleaner appearance or to maximize vegetative growth. Not deadheading these roses or any rose whose rebloom is less than showy allows us to take advantage of the ornamental value of fall hip display.
Methods for deadheading should vary between types of roses. For instance, the usual method of deadheading Hybrid Teas and Floribundas is to remove a spent flower and the cane beneath it back to the first outward-facing leaf with five leaflets. If the plant is young, small, or not doing well, remove as little foliage as possible. Deadheading back to a leaf with fewer leaflets often results in non-flowering new growth, called blind wood.
The location of new shoot and new flower formation is more variable among hardy repeat-flowering roses. New flowering wood can be produced from a bud at the bract beneath a flower or from buds at any leaf axis. On these roses, it is better to deadhead back to the bract beneath the flower, and observe whether new flowering wood grows from this point. If flowers are not produced, prune back to the first leaf and start the observation process again. Continue deadheading back to the highest leaf on a cane until you know the pattern or growth and bloom for a cultivar.
Do not deadhead about six weeks before your expected first frost (mid-October for most of you). This allows hips to form, which signals the plant to slow its growth and go dormant in preparation for winter.
For more information about this and other landscape topics contact your local Virginia Cooperative Extension office. The local Virginia Cooperative Extension office numbers are Albemarle 872-4580, Fluvanna 591-1950, Greene 985-5236, Louisa 540-967-3422, and Nelson 263-4035.