Gardening with Allen: Removing dead flowers can increase blooms, appearance
By Allen Wilson
Published: August 7, 2021, 6:05am
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I have a neighbor who removes the dead flowers from all of her plants. She says it makes them bloom more. Does that really make plants bloom more?
The main reason for removing old, dead flowers (referred to as “dead-heading”) is to improve the appearance of the landscape. However, dead-heading will also increase the number of blooms on many annual and perennial flowers. Plants produce flowers to reproduce themselves. After a flower has been pollinated and produces seeds, plants often consider their job done. When dead flowers are removed before seeds are produced, many plants are stimulated to bloom again. However, most shrubs and many perennial flowers only produce one set of blooms at a specific time of year and will not bloom again even if the flowers are removed.
I sometimes prune the dead flowers off of shrubs while I am doing other pruning or cleanup. Then I will remove some dead flowers to improve their appearance. There are some varieties of flowering shrubs such as barberry and spiraea that also have colorful new leaf growth as well as flowers. Some summer blooming shrubs such as hydrangea and potentilla will produce more flowers if they are dead-headed.
Some of our most popular annual flowers continue blooming whether flowers are removed or not. Some either drop old flowers naturally or grow new leaves that cover the dead flowers. Petunias, impatiens, begonias, marigolds, pansies, zinnias, alyssum and lobelia fit in this group. They continue to bloom and make a colorful show even without dead-heading.
Most perennial flowers benefit from dead-heading. Shasta daisy, delphinium, campanula, coneflower, columbine, Iceland poppy, penstemon, lupine, lavender, hollyhock and coreopsis will all produce more flowers if dead-headed.
A few flowers are grown for their colorful leaves. Coleus, heuchera and hosta have colorful foliage all summer. Their flowers are secondary and sometimes even unattractive. These three also grow in shade and semi-shade where most annual flowers do not do well.
More and more perennial flowers are being created that bloom as continuously as our popular annuals. I have planted some of these where I used to grow annuals. Lamium (spotted nettle) is a 3- to 5-inch ground cover with white, pink, lavender or crimson flowers that blooms from April to October. It grows best in semi-shade. Moonbeam coreopsis has lemon-yellow daisy flowers and grows about 16-20 inches tall in full sun. It blooms from late June to October. Rozanne is a perennial geranium with sky blue flowers. It grows about 18 inches in full sun or 24 inches with a half-day of sun.
In recent years new garden-size plants have been developed of one of the most popular cut flowers. Alstroemeria is commonly referred to as Lily of the Incas or Peruvian Lily. Varieties in a full range of colors including scarlet and crimson red, pink, orange, lavender, yellow and creamy white range from 8 to 15 inches in height. They bloom from June to October. Plants are often available in full service nurseries in mid- to late summer.
