Four Good Reasons to Deadhead Flowers

1. Prolong the Bloom

Removing spent flowerheads is one of the best ways to extend the show. By not allowing your flowering plants to set seeds, they will keep producing more flowers. Their mission is not to provide you with beauty, but to ensure the survival of their species by making seeds that turn into next year’s plants. Once they have accomplished that task, they shut down the bloom factory. Perennials have a well-defined season of bloom, but most annuals will keep on pumping out the blossoms until seeds form. By deadheading them, all that energy needed to produce seeds will go right back into forming more flowers.

2. Control Self-Sowers

I don’t know about you, but I have many rampant self-sowers in my garden whose goal is to take over the earth. To keep them under control, I have to be diligent about removing their spent flowers before they can disperse their seeds. Keep an eye on these self-seeders:

• columbine
• mallow
• violets
• phlox
• clustered bellflower
• evening primrose
• foxglove

Often, I will let a few form seeds at the end of their season of bloom and scatter the seeds in places where I’d like them to grow.

3. Encourage Reblooming

Quite a few perennials will reward you with a second flush of flowers later in the season if you remove the spent spring or early summer blossoms. Here are some of the ones that may produce a second round of flower stalks in late summer:

• delphinium
• columbine
• cardinal flower
• tiarella
• foxglove
• centranthus
• hollyhocks

Leave the foliage alone and just cut the old flowering stalks to the ground, then give the plants a boost by sidedressing with compost or organic fertilizer. With luck, you just might get a second crop of flowers.

4. Tidy Up

Keep your garden looking its best by removing faded flowers before they wither and turn brown. Some flowers are sold as “self-cleaning,” meaning they will push off their dead blossoms without your help. You still might want to check and see if they have left a seedpod behind.

Don’t worry about deadheading impatiens, vinca, or sedums. Even if they form seeds, it does not impair their ability to keep blooming.

Narrow-leaf or creeping zinnias don’t need to be deadheaded, but doing so will encourage new blooms to form faster.

I try to remove the spent blossoms on my big rhododendrons just to give a cleaner look to the shrub and to make way for the new growth that forms at the base of the old flowers. It’s not imperative to do so. The new growth will form, masking the dead flowers, which eventually dry up and fall off by themselves. The plants are now so tall that I would need a ladder to reach the uppermost branches anyway!

How to Deadhead

Pinch or cut off all of the old blossom—not just the petals—before it can set seeds. Try not to leave stumps.

Leave as much foliage as you can, as it’s where the plant gets its energy. If you have multiple flowers on a single stalk, like hollyhocks or foxglove, carefully remove each spent blossom from the bottom up while allowing the top buds to develop and bloom. When the stalk is finally spent, cut it off at the base.

On plants such as dianthus, baby’s breath, spirea, and thread-leaf coreopsis, it is hard to remove single blossoms as they fade. I wait until they are done blooming and take the hedge clippers to them, shearing off as many of the dead blossoms as possible. Not very accurate, but it is quick and efficient. I try to remove the old lilac flowers that I can reach. They also form new growth at the base of the old flowers.

Whether you perform this task weekly or every time you pass by a plant, it doesn’t take long to either snap or snip off spent blossoms. I try to carry a small pair of clippers with me, but often forget and end up just using my fingers. If a cleaner, more accurate cut is needed, I’ll wait until I am better prepared. 

As fall approaches, I start to leave the seedheads for the birds to enjoy.

Read more about plants with seedheads that you can leave to feed the birds until spring.