By Andrew Bunting, PHS VP of Horticulture 

Ever wondered, 'What is deadheading?' You're not alone. Deadheading is a gardening term that refers to the process of removing spent flowers.  ‘Grooming’ is another closely related term that includes the removal of old flowers, broken plant parts, old leaves, and more.  Deadheading helps keep your ornamental containers and garden beds looking tidy, fresh, and luxuriant through the growing season. It also keeps plants vigorous — instead of energy going into seed production, the plant’s energy goes into producing more flowers. 

What Flowers Should You Deadhead?  

Deadheading flowers benefits most ornamental flowering annuals and perennials, making them look lush and vibrant. Popular flowering annuals like salvia, petunias, marigolds, zinnias, Angelonia, dahlias, Pentas, Celosia, and others will have a much better flower display by removing old flowers. This can be done as a regular activity when you’re doing other grooming activities or also in tandem with watering.  Just like these annuals, many perennials such as hostas, Astilbe, lilies, daylilies, coneflowers, Rudbeckia, and Veronica also respond well to deadheading.  

How to Deadhead Flowers 

The art of deadheading flowers differs for each plant variety. For low-growing plants with a profusion of flowers like petunias, Lantana or Calibrachoa, deadheading might be as simple as plucking or pinching off the flowers with your fingers or fingernails.  

For flowers that have longer stalks like zinnias, salvia, geraniums, dahlias, hostas, or coneflowers, a special tool will be needed. The thickness of the flower stems will determine the type of cutting device. There are small pruners that are perfect for thin stems. For thicker stems, good scissor-like pruning shears will be needed. It is important to get the type of shears that have an upper and lower blade that cut through the stem versus the anvil-type of pruner where the upper blade is scissor-like, but the lower blade is stationary and flat. This anvil-type results in the flower stem being cut and crushed at the same time which will harm the plant. 

The flower stem should be cut back to where there are leaves. For some plants like hostas and daylilies, the entire flowering stalk can be removed when all the flowering on the stem is finished. This often means that the relatively thick stem is cut all the way back to the ground. 

All deadheaded flowers that are removed can be put on a compost pile or put into a composting bin and treated like any other compostable organic matter. 

When Not to Deadhead 

Deadheading flowers isn't always necessary. Some plants produce ornamental seedheads if the flowers are left intact, and in these cases, you might choose not to deadhead. Some examples of plants with attractive seedheads include the ornamental onions, Allium; love-in-a-mist, Nigella damascena, money plant, Lunaria annua; quaking grass, Briza maxima; and prairie smoke, Geum triflorum. 

If you are already leaving the seedheads for ornamental reasons, they might also be left for wildlife. Therefore, deadheading should not occur if the garden is meant to be a seed source, especially for seed eating birds such as sparrows, finches, etc.  Plants like the giant rudbeckia, Rudbeckia maxima, and the coneflowers, Echinacea are excellent sources of seeds for birds, as well as species of Helianthus, Gaillardia, and asters. 

The Benefits of Deadheading Flowers 

Deadheading is more than a gardening task — it's a way to keep your garden flourishing. It keeps your plants, particularly annuals, vibrant and healthy throughout the growing season and can easily become a part of your daily routine.  By taking a few minutes to snip away spent flowers, you're investing in a garden that thrives and produces even more beautiful flowers. With consistent care, deadheading is a tactic that can help transform your garden.