Most gardeners understand there is a reason for deadheading, right? If I asked you, you’ll most likely say it’s because if the plant isn’t deadheaded, its energy goes towards seed set, and it will no longer continue to bloom as it should or could. And you’d be right.
SEEDS FOR THE BIRDS
Before we get into the ways of deadheading, I want to ask you: is growing more flowers your only goal? Could there be other benefits than just flowers? Of course there are. Read on!
What if you want more flowers and seeds for the birds? This is where you learn the deadheading boogie dance. OK, I made that up, but it makes sense. If you want more blooms and birds, only deadhead half of the seed-heads.
Did you know Goldfinch, Spinus tristis, delay nesting until there are enough seed available to feed their young is available? Goldfinches are one of the few birds that are strictly vegetarian. Personally, I find goldfinch feeding on seed just as beautiful, if not more, than the flower itself.
GENERAL DEADHEADING
Perennials/Shrubs
Asters, Asteraceae spp.—Typically, there are so many long-lasting flowers, I tend to give this a pass.
Bee Balm, Monarda spp.—Deadhead to the next bud. When the flowers have finished fleshing out, cut to the ground, you’ll get another flowering round of this old fashion favorite.
There are several composite flowers where deadheading procedures are the same to produce regrowth: Black-eyed Susans, Rudbeckia spp., blanket flower, Gaillardia spp., coneflowers, Echinacea spp. When I see the next bud forming below, I deadhead to just above that new bud.
Daylilies, Hemerocallis spp.—As the name suggests, daylilies last but a day. They will fall off themselves after a day or two, but to really tidy up the plant, go ahead and pull them off after a day. I have friends who like to spend their evenings, often with a toddy in hand, cutting that day’s bloom before morning arrives. That way, the day starts fresh!
Foxglove, Digitalis purpurea—With flowers that bloom from bottom, up like Foxglove, Gladiolus, Liatris, it’s best to deadhead when only 25% of flowers remain.
Hollyhocks, Alcea spp.—Anyone who has ever grown this great plant knows hollyhocks are known for the fungal disease rust. I found that once the flowers are spent, cut it way back, leaves and all. You will get a new flush of flowers, and the rust tends to be at bay by then. Hollyhocks are also the lost butterfly plant for the Painted Lady butterfly.
Iris spp.—You’ll want to cut back these spent stalks not just to get fresh flowers but also to make the plant look better.
Joe-Pye weed, Eutrochium purpureum—As for Joe-Pye weed, I don’t tend to deadhead. The flowers are fluffy, look good, and don’t tend to make more once they finish blooming. Joe-Pye weed is also the host plant for 47 caterpillars, primarily moths, producing good food for brooding birds.
Garden Phlox, Phlox paniculata—Seed-eating birds love the seed.
Rose, Rosa spp.—If you grow roses, you know how to deadhead; if you are a new rosarian, cut spent bloom back to a five-leaflet petiole, cutting at an angle, just above a leaflet facing outward.
Before deadheading
After
Sage, Salvia officinalis—Don’t let this one sneak up on you. Keep deadheaded, and this salvia will bloom all summer.
Blue salvia, Salvia guaranitica—Blue Salvia will bloom all summer regardless of deadheading. In a big patch, do tend to cut half of the plants back by half. This will delay blooming and will keep a stouter plant.
Shasta Daisy—I know people who don’t deadhead Shastas until all the flowers are all spent. Then they shear for the next flush. I don’t do this and find it difficult to accept. I like to groom my plants lovingly and don’t like the harsh effects of shearing.
Tickseed—There are too many flowers to deadhead. You’ll extend the bloom, but the goldfinch loves these seeds.
Annuals/Biennials
Cleome, Cleome hassleriana—I love this old-fashioned spider plant until I don’t. Once they go to seed, the “arms” look gangly, and I find them to be very unattractive. As soon as I collect seeds for next year, I pull them up and compost.
Coleus, Coleus scutellarioides—Coleus are grown for the foliage. The bees like the flowers, but most of us will snip back the flowers to highlight the leaves.
Campanulas, Campanula spp.—This baby spreads so much, no need to deadhead. They will make more.
Cosmos, Cosmos bipinnatus—These spring beauties will last a long time if deadheaded to the next node.
Hardy Geraniums, Geranium bohemicum—This is another one I don’t tend to deadhead because there are so many long-lasting flowers.
Larkspur, Delphinium spp.—I’m greedy where Larkspur is concerned. I let them all go to seed so I can collect the seed for next year. They will self-sow, but I like collecting them to move around and share. Once this is done, I pull and compost.
Marigolds, Tagetes spp.—For marigolds, I deadhead the first half of summer to let them flush, then stop the second half so I can collect seed.
Petunias spp.—I do deadhead petunias, but I also have a trick where I cut back hard the week before I go on vacation. That why I have an entirely new flush when I return!
Snapdragons, Antirrhinum spp.—Deadheading will increase your floral display.
Zinnia spp.—Zinnias can be deadheaded a few times but will ultimately get gangly. Deadhead a couple of times, and when the plant starts to look ratty, cut back to the ground. Depending on the time of year, it may or may not flush back.
Good luck, and experiment. Deadheading allows us to get more from our flowers!