Key Points
Deadheading extends blooms, but letting some set seed helps wildlife and the garden.Stop deadheading once plants need to produce seed for the season’s end.Know your plant’s bloom cycle and watch for slowing growth as a signal.
Deadheading is an essential home gardener’s hack to keep some flowers in bloom for longer and make your borders look tidier. But when do you stop snipping if you want to let your plant shift to making seeds?
Allowing seed heads to form supports more flowers next year—especially in reliable reseeders like sweet peas, calendula, and coneflowers—offers winter landscape interest and provides food for wildlife when harsh weather hits.
Here are six signs it’s time to stop deadheading flowers and start letting nature take its course.
Seasonal Changes
Cooler temperatures and shorter days with less sun can signal the end of the bloom season for many species. However, some stop blooming earlier in the year. Knowing the typical bloom span of your annuals and perennials helps you recognize when the curtain is closing on the deadheading season.
Weather extremes can also affect the length of your flowering season. If you’re experiencing early cold snaps or plant-stressing scorching fall temperatures, reblooming may be less likely.
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Fewer Buds Are Forming
Has your healthy plant gone from readily cranking out a bunch of buds to only producing a paltry amount? Maybe the ones it does produce stay tightly closed or drop off prematurely?
This can be a sign that it’s redirecting its energy towards seed production or, in the case of perennials like salvias, Shasta daisies, or yarrow, stocking up its root reserves in preparation for entering winter dormancy.
Blooms Are Smaller and Less Vibrant
If new flowers forming are smaller, faded, malformed or generally just less vibrant, this could be a sign your plant is losing steam for the season.
Sometimes, instead of new petals developing on flowers, you may see green bracts, pods or husks. This isn’t a sign that something is wrong—these form to act as protective seed containers.
Plant Growth Slows and Foliage Fades
Don’t continue to deadhead if you notice your plant starting to look less vigorous towards the end of its season. Even with consistent water and care, perennials may start yellowing or dropping leaves as they slip into dormancy. Annuals, meanwhile, may simply fade as their life cycle ends.
This slowdown reflects a reallocation of resources. Rather than investing in foliage or flowers, the plant channels energy into ripening seeds and, in the case of perennials, storing carbohydrates in roots for winter survival.
Recognizing this shift allows you to embrace nature instead of fighting it by over-fertilizing or cutting back aggressively.
Fewer Pollinators
Are you seeing a drop in bees, butterflies and hummingbirds gathering around the flowers in your pollinator-friendly garden? This could mean there are fewer viable nectar-rich blooms available for them to feed on because your plants are getting ready to set seed.
Seedheads Are Already Forming
If you’ve been deadheading regularly and your flowers are reaching the end of their expected bloom season, it’s time to cut back on the cutting. Maybe you aren’t sure if you can squeeze in one last flush of flowers? In this case, you could deadhead some and let others set seed.
Avoid deadheading flowers that already have seed pods forming. A subtle sign that this is happening is the swelling of the ovary at the base of spent blooms.
This might start out green and fleshy and then harden as it matures and the seeds develop.
Some plants, such as sunflowers and poppies, have more visible, decorative seed capsules, heads or pods. A good example is purple coneflowers. Their striking violet petals fade, but the dark spiky centers harden into ornamental seed heads that the finches and cardinals will be grateful for as their other food sources dry up in winter.
In other species, the seed heads might not be so immediately obvious. However, once the seedheads of your plant are fully developed, you can leave them for the birds and wind to scatter the dry seeds naturally and to provide winter interest and wildlife nutrients.
Alternatively, you can harvest them yourself once dry, storing them in paper envelopes for reseeding next spring.
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