Why and when to deadhead your flowers
Deadheading is an old botanic term that simply means “to remove the old spent blooms to help keep it blooming longer”.
In truth it is rarely going to be a bad thing to clip off dead blooms. For one thing the plant usually looks better, and removing old flowers is a good way to avoid disease issues and encourages more new flowers sooner, BUT it is a lot of work, so for those of us who would rather enjoy our gardens than work in them, most Proven Winners® flowers do not need to be deadheaded.
The simple truth is 20 years ago when almost all plants were sold as seed, deadheading made a lot more sense. If a plant grows from seed then it must set new seed each year to keep growing. However, setting seed comes with a price and that price is fewer flowers, so gardeners learned to remove old flowers (and the seed inside them) in order to keep their plants blooming longer. Now that we grow a lot of plants from cuttings and not seed, we can select for the plants that do not produce seed and get better, longer lived flowers for home and garden. So a lot of our flowers are sterile or only rarely produce seed because this makes them produce more flowers, longer through the season.
However there are some plants that do like to have the old flowers removed and it will really help to bring more new flowers faster if you learn how to do it correctly. It is very simple!
On short stemmed flowers (like Calibrachoa, Petunia, Lobelia), just trim off old blooms or seed pods and remove any stems where there are no flowers forming.
On long stemmed flowers (like Gerbera Daisy, Heuchera, Shasta Daisy) remove each flower stalk as low to the ground as possible without damaging surrounding leaves.
REMEMBER: Deadheading should be done in spring to early summer, waiting until late summer or fall to begin deadheading is usually too late and the shortening days of fall and cooler temperatures will work against the growth of new flowers.
While a good rule of thumb is always nice to have, a list of how to deadhead specific plants is also useful. Here is a list of many of our plants and those that do not need to be deadheaded and some that may benefit from removing old flowers.
Deadheading not needed
Catalina® and Summer Wave® Torenia
Flambe® Yellow Chrysocephalum
Pink Chablis® Lamium
Señorita Rosalita® Cleome
Snow Princess® Lobularia
Soprano™ and Symphony Osteospermum
Superbena® and Tukana® Verbena
Sweet Romance® Lavender
Whirlwind® and New Wonder® Scaevola
Deadheading can extend flowering season
Amazing Daisies™ Leucanthemum