The short version: Deadheading means taking a flower off once it fades, before it sets seed. Many annuals slow right down once seed ripens. Cut the spent flower back to the next leaf, bud or branching point, or right out at the base on rosette plants such as gerbera. Ten minutes once a week suits most gardens. Leave the last flush to ripen if you want self seeders, saved seed, or seed heads for the birds.
There is a moment in December when a bed of cosmos stops looking like a flower bed and starts looking like a hedge with a few blooms on top. Down among the leaves, two dozen flowers have turned into seed heads, and the plant has taken that as the finish line.
Deadheading moves the finish line.
Removing a fading flower keeps the plant producing
A flower is not the point of the plant. Seed is. Once a bloom is pollinated, the plant sends sugars and nutrients into that seed, and for most annuals ripe seed is the signal that the season is over. Take the flower off first and the plant never gets that signal, so it sets more buds. Gardening Australia makes the same point about roses.
The detail underneath is less tidy. Ripening seed draws heavily on the plant's resources, and it also produces hormone signals that can slow new bud formation, though this varies between species.
Where to cut, on five kinds of plant
The cut is almost never just under the flower: aim for the nearest point that can grow something new.
- One flower on a long stem. Cut back to just above the next leaf, bud or side shoot, leaving no bare stub.
- Branching plants with one flower per stem, such as cosmos and zinnias. Trace the stem down to the first pair of leaves with a shoot in the joint, and cut above it. The plant branches there, two stems for one.
- Spikes, such as snapdragons, larkspur and delphiniums. Florets open from the bottom up, so a spike looks half finished for days. Once most of it is over, cut the spike to a leaf or side shoot lower down. Snapdragons often give a second, shorter flush.
- Rosette plants, such as gerbera and some daisies. The flower rises on a bare stem out of the crown, so take the whole stem out at the base, where a stub would hold water.
- Carpets of tiny flowers, such as alyssum. There are far too many to deal with one at a time, so shear the plant back by about a third, then water and feed it. Leggy marigolds take the same treatment.
Pinching and picking for the vase are the same job
Pinching comes first: taking the tip out of a young plant above a pair of leaves forces two shoots from that joint, which is why a pinched cosmos carries more stems. It is the logic of pinching basil. Picking for the house is deadheading too, and better, because the bloom comes off while it is still perfect.
The flowers that pay you back most
Not every plant responds. These do:
- Annuals that stop without you: sweet pea, cosmos, zinnia, marigold, calendula, snapdragon, upright petunia.
- Tubers and perennials: dahlia, gaura (frost hardy, and a seeder along roadsides, so cut the spent wands back), and the pelargoniums most of us call geraniums.
- Repeat flowering shrubs and perennials: roses, perennial salvias, coreopsis.
Four plants with rules of their own
Roses. The old instruction is to cut to the first outward facing leaf with five leaflets. The principle is sound, because you want a bud strong enough to grow, but on modern repeat flowering roses it matters less. From late summer, cut spent stems back by five or six buds to an outward facing bud for a stronger autumn flush.
Dahlias. A spent dahlia closes back up and looks maddeningly like a new bud. The difference is shape: a fresh bud is round like a green marble, a spent head pointed and soft. Cut it well down to a pair of leaves.
Sweet peas. Pick every few days, and pick everything, because once pods start ripening the vine winds down.
Bulbs. Snap off the faded flower with the swollen green pod behind the petals, then leave every leaf until it yellows, because the leaves are refilling the bulb.
What to leave alone, and when to stop
- Self seeders you want back. Shirley and Iceland poppies, nigella, larkspur and calendula return from dropped seed, and so does honesty, which seeds freely enough to keep well inside the garden. Californian poppy is the exception: Weeds of Australia records it as an environmental weed in Western Australia, New South Wales and Victoria, so deadhead that one, especially near bushland. Our guide to self-seeding flowers covers the ones that behave.
- Plants grown for seed heads or hips. Nigella pods, honesty discs and rose hips are the display.
- Anything you are saving seed from. Mark those plants early, and see seed saving for beginners.
- Self cleaning and sterile varieties. Many trailing petunias, most impatiens and plenty of begonias shed spent flowers themselves, and some hybrids set no seed. Lobelia, diascia, nemesia and bacopa are the other classic self tidiers.
- Late flowers left for wildlife. BirdLife Australia recommends native grasses for their seed heads, which feed finches and other seed eaters such as rosellas. A standing sunflower head does the same.
If you want seed, stop deadheading a few plants about six weeks before the display ends, so heads dry on the stem. For roses in frost prone districts, ease off six to eight weeks before your first frost, so no soft growth meets a cold snap.
Deadheading is sometimes a duty. Many of Australia's environmental weeds began as garden plants, as the Invasive Species Council has documented, so cut anything with a name for jumping the fence before it seeds, gaura and Californian poppy included, and check your state weed list.
Tools, hygiene and one safe habit
Fingers work on soft stems: cosmos, calendula and petunias pinch off with a thumbnail. Anything woody wants sharp snips, because a crushed stem invites disease.
Wipe the blades between plants if you have been cutting anything diseased: clean the sap off first, then wipe with methylated spirits or dip in one part bleach to ten parts water.
Snips are sharp, so cut away from your other hand, close them when you put them down, keep them from children, wear gloves for roses and for anything whose sap has ever bothered your skin, and wash sap off before it dries. Our notes on staying safe in the garden go further.
How often is enough
Once a week, for about ten minutes, keeps most home gardens in flower. Start at one end of the bed and cut anything faded as you pass, and walk it twice in peak heat, when flowers go over in days.
When the deadheading season runs, zone by zone
These are broad groupings, so your own frost dates and soil temperature overrule the month. No single authority publishes a flowering calendar for the whole country.
- Tropical (Darwin in the Northern Territory, Cairns and Townsville in Queensland): the dry season, roughly May to October. Through the wet, cut spent flowers to keep rot out.
- Subtropical (Brisbane, the Sunshine Coast and the Gold Coast in Queensland, Coffs Harbour and Lismore in northern New South Wales): roughly September to May, heaviest in humid late summer.
- Arid and semi-arid (Alice Springs in the Northern Territory, Broken Hill in New South Wales, Mildura in Victoria, Kalgoorlie in Western Australia, inland and central-west Queensland): spring and autumn are the peaks. In extreme heat, deadhead lightly.
- Temperate (Sydney, Newcastle and Wollongong in New South Wales, Melbourne and Geelong in Victoria at the cold end of the zone): roughly October to April, the longest run in the country.
- Mediterranean (Perth, Bunbury and Geraldton in Western Australia, Adelaide and the Barossa in South Australia): September to about May, working in the cool of the morning.
- Cool and alpine (Tasmania, Canberra and the ACT, Ballarat in Victoria, Orange, Bathurst and Armidale in New South Wales, Stanthorpe in Queensland): a shorter run, about November to April, ending with the first frost.
Frequently asked questions
Do I really have to deadhead, or will the garden be fine without it?
The garden will be fine, it will just flower for less of the season. Cosmos, zinnias and sweet peas notice most.
Can I just pull the dead flowers off with my fingers?
Yes, on soft stems. Petunias, pelargoniums, calendula and marigolds pinch off cleanly, but use snips on anything woody. Take the whole stalk, not just the petals.
My cosmos have gone tall and leggy with hardly any flowers. Is it too late?
Usually not. Cut it back by about a third, water and feed it, and it will often branch and flower again within a month.
Should I deadhead if I want to save seed?
Deadhead for most of the season, then stop on a few plants and let those heads dry on the stem. Mark them with a ribbon so nobody tidies them away.
Where do the spent heads go, and can they be composted?
Most go straight into the compost. The exceptions are anything diseased or weedy, since a home heap rarely gets hot enough to kill every seed.
Do Australian native flowers need deadheading?
Some do. On everlasting daisies the papery bracts are the flower itself, so pick them at their best for drying, and cut spent heads back to a leaf to keep the plant branching. Leave a few late heads if you want seedlings. Kangaroo paw stems are cut at the base.
Deadheading feels like fussing until the January afternoon you notice the bed is still full of flowers and the one next door is not.
Related growing guides
Start with the branching annuals: our cosmos seeds and zinnia seeds keep going for months when you keep cutting.