As we move further into summer, you may discover that some of your annuals and perennials that were blooming so heavily a week or two ago have begun to slow down. While some plants have a limited bloom period that really can't be stretched (especially trees, shrubs, and perennials), most annuals and many perennials will continue to bloom, though maybe less profusely, with the help of deadheading.
Image source: agriculture.purdue.edu
Deadheading is the removal of spent blooms. It can tidy up the appearance of a plant or promote flowering. Why does it increase flowering? When you remove an old flower, the plant loses its future seeds. This triggers the plant to produce more flowers so that it can make seeds to reproduce. Technically, deadheading is a stress on the plant, but it's an extremely minor stress that gives us good results from an aesthetic standpoint. On plants with woody or stiff stems, you can use pruners to cut below the flower head down to the next leaves or stems, but in some cases the stem is tender enough that you can just pinch or snap off the spent flower with your fingers. If you're dealing with a plant covered in tiny blossoms, shearing from time to time may be easier than removing each individual bloom. The following annuals, perennials, and shrubs will re-bloom, at least to some extent, if deadheaded.
Annuals:
- Verbena (self-deadheading varieties available)
- Petunia (self-deadheading varieties available)
- Geranium
- Lantana
- Marigold
- Scarlet Sage
- Snapdragon
- Heliotrope
- Sweet Alyssum (self-deadheading varieties available)
- Begonia
- Zinnia
- Lobelia
Perennials:
- Shasta Daisy
- Garden Phlox
- Daylily
- Coreopsis
- Salvia
- Yarrow
- Purple Coneflower
- Hardy Geranium
- Dianthus
- Hollyhock
- Aster
- Bleeding Hearts
- Gaillardia/Blanket Flower
- Hardy Hibiscus
- Liatris/Blazing Star/Gayfeather
- Black-Eyed Susan
- Bee Balm
Shrubs:
- Knock-Out Rose
- Bloomerang Lilac
- Sonic Bloom Weigela
- Butterfly Bush
Snapdragon
Photo by Maria Gulley
Purple Coneflower
Photo by Maria Gulley
Rose
Photo by Maria Gulley
Many annuals are now being bred to deadhead themselves. This saves a lot of time maintaining containers and summer annual beds because we want them covered in flowers all summer, and it would be a pain if we had to pull off each declining flower. Here is a short list of annuals that are covered in color all summer long without deadheading. More options are coming out all the time, so be sure to check plant labels or ask for recommendations at the garden center.
- Snow Princess Sweet Alyssum
- Wave Petunia
- Supertunia Petunia
- Superbena Verbena
- Impatiens
- Artist Ageratum
- Bidens
- Superbells Calibrachoa
- Diamond Frost Euphorbia
- Laguna and Lucia Lobelia
- Snowstorm Bacopa
