If you’re new to gardening you may wonder why you see an experienced gardener pulling the spent blooms off their rose bush. Or snipping the flowers off a daffodil. They’re doing a simple kind of pruning called deadheading.
With deadheading, old growth and seed heads are “pinched” or cut off the plant to stimulate new growth and more flowers. As the only purpose (botanically speaking) of a flowering plant is to bloom and then set seed, deadheading tricks the plant into producing new blooms so it can set more seed. This extends the blooming season of the plant. It also keeps certain species from reseeding and keeps flowers and shrubs looking fresh and lively throughout the season.
After a plant is finished flowering, it begins to form seeds. The flowering process is suspended, and the plant begins to use all its energy to form seeds. Deadheading plants as soon as the blooms begin to fade will promote a second bloom…
When dead blooms are left clinging to flowering plants, they sap the nutrition and strength from the core of the plants and rob them of the energy to produce new and colorful blooms. The deadheading process redirects plants energy from seed production to root and vegetative growth.
To Deadhead or Not?, Penn State Extension
How to deadhead flowers
There’s nothing to be hesitant about, as deadheading is very simple and good for the plant. As flower blooms start to look scruffy, “pinch” them at the base where they meet the stem and gently pull the spent bloom from the plant. For thicker stems like roses, cut the flower stems in between the dying bloom and the closest set of healthy leaves. But take care that you don’t snip off new flower buds!
A note about deadheading roses: Some varieties of roses produce rose hips at the base of the flower, like those seen in the image above of pinching. The hip is the fruit of a rose and contains many small seeds. If left on the plant, the hips will swell and fill with natural sugars and a high level of vitamin C. They’re an important source of food for wildlife in the fall, are very colorful, and are also used in foods like teas and jams. So if your rose produces hips, you may wish not to deadhead your plant or deadhead just a portion of it as I do.
When to deadhead flowers
A flower bloom can last from one day to several weeks and weather conditions like heat, wind, and rain affect blooming a great deal. A simple walk around your garden once a day will show you which plants need deadheading and which don’t.
Deadhead a flower as soon as the bloom starts to decline and looks like it’s seen better days. How often depends on the plant, but a little observation will help you figure it out.
- A daylily bloom fades after – you guessed it – one day. The daylily deadheads itself and the dying bloom will fall off after a few days. But deadheading makes the plant look nicer.
- A peony bloom lasts for roughly one week, but when on the decline, scatters its petals in a thick mass below the plant (this might be good or bad depending on your point of view). Additionally, deadheading can encourage some varieties to produce side buds after the main bud blooms.
- Deadheading can stimulate new blooms on many flowering plants such as marigolds, zinnias, hollyhocks, and butterfly bush. (see chart below)
Not all flowering plants should be deadheaded
Don’t deadhead everything you see. Some flowering plants like Hollyhock, Columbine, and Foxglove can be left to go to seed so that you’ll see them again next year. Columbines may produce new plants from seed in the same season. So you may wish to let these plants go their natural course. Reserve your deadheading for daylilies, roses, astilbe, coreopsis, Monarda (bee balm), and others.
Consider stopping deadheading in the fall. As food supplies dwindle for birds and other wildlife, flower seed heads become an important source of nutrition. Leave most flower heads intact at the end of the season, as you’re past the time that plants can produce new blooms. Plus, some seed heads are beautiful in the fall as they die back and turn to yellow, red, or brown against a winter landscape.
Here’s a great video from Fraser Valley Rose Farm on techniques for deadheading many annuals and perennials.
Sources: To Deadhead or not your final answer is, Penn State Extension; Plant Talk, Colorado State University; Deadheading Herbaceous Ornamentals and Roses, Iowa State University Extension.
