To "deadhead" plants means to remove their spent flowers. For many plants, removing the blooms after they have gone by promotes more flowering on them for that year than would occur without such plant care. Gardeners also take the old blossoms off simply to keep ugly, shriveled-up flowers from marring the appearance of a planting bed.
Incidentally, fans of Jerry Garcia (from the band, the Grateful Dead) will be quick to point out that they call themselves "Deadheads." But note that, in this case, the word begins with a capital "D."
How to Deadhead a Plant
For soft plants, you can deadhead by hand (although it still helps to have long fingernails), pinching the stem between your thumb and forefinger. For those with tougher stems, you may need pruners to make your cut. Be sure to remove the entire flower. Many beginners make the mistake of removing just the petals, missing the part of the flower where the seeds are actually forming (which defeats the main purpose of deadheading). Note: "Deadhead" and "pinch" are very similar terms. Some people use them interchangeably. Others make a technical distinction, insisting that you "pinch back" a plant before it flowers, to make its vegetation bushier; whereas you can only "deadhead" a plant, by definition, after it has flowered (since it is the "dead" flower "heads" that you are removing).
But most gardeners will not want to quibble over such distinctions. Indeed, you do not always have to be fussy about the operation.
Some plants can be sheared to yield the same effect as deadheading, in the long run. For example, I give my sweet alyssum (a short plant that can be used as an annual ground cover) a good haircut with a pair of scissors to generate re-blooming on it. It really depends on the type of plant you have.
You would be more careful with a tall perennial that has long, leafless flower stems. For that type of plant, you would deadhead by removing individual flower stems once the flower or flowers have passed (since, being totally bare now, the leftover stem would be unsightly if allowed to remain). For other plants, a good place for a cut may be down to a place on the stem where there is a lateral leaf.
Promoting Re-Blooming by Deadheading: How It Works
After giving these distinctions their due, the fact still remains that all these various deadheading methods are governed by a similar principle: it is all about channeling a plant's energy into a direction that you find more agreeable than the "natural" direction. When you deadhead flowers, you are channeling energy away from seed production and into further flower production. In essence, to "deadhead" a plant is to trick it into forming additional flowers, in its attempt to (finally) produce the seed it set out to produce in the first place, before you deadheaded it.
Think of it this way. The plant's game plan is to reproduce by forming seeds. This conflicts with your own plan, which is to enjoy flowers for as long as possible (once they go to seed, the floral show is over). You, as the gardener, have the right to tell your plant (by deadheading it), part-way through the game, "Hey, plant, I am overriding your plan: you will be waiting a bit longer to form those seeds." Do not worry: the operation does no harm to the plant. In fact, both parties should be quite happy with the results.
Which Plants Should I Deadhead?
Not all plants need to be deadheaded. But it is generally a good idea to remove the spent flowers from your annual plants if you wish to achieve maximal landscaping with four-season interest. Deadheading gives many of them the chance to continue blooming throughout the summer and, in some cases, right into the autumn (annuals thus treated can expand your fall-flower choices). Sometimes, a plant cries out to have its flowers removed, so that the decision on your part is a no-brainer. For example, petunias look horrible after a rainstorm; this provides the perfect excuse to deadhead them. Many perennial flowers, too, profit from the operation. Repeat-flowering rose bushes (such as hybrid tea roses and floribunda roses) are examples of shrubs that you should deadhead if you want more blossoms from them.
Without deadheading, some annual flowers will "peter out" prematurely, robbing the landscape of the color they can provide in late summer and/or early autumn. And the comparatively short blooming season of some perennials can be extended if you deadhead them. The following is a list of some of the annuals and perennials to focus your deadheading efforts upon:
Short List of Plants That May Flower Longer if Deadheaded:
- Bee balm
- Butterfly weed
- Garden phlox
- Geraniums (Pelargonium)
- Italian bugloss
- Rose campion
- Salvia (perennial)
- Shasta daisies
- Speedwells (the kinds that produce flower spikes)
Where to Go Next
If you are interested in deadheading plants to promote re-blooming, then you will probably also wish to read about long-blooming perennials that flower all summer.