Why a few minutes with the secateurs pays off

Every flower has a job, and that job is to make seed. Once a bloom has been pollinated and starts to fade, the plant switches its energy from producing more buds to swelling and ripening seed. Deadheading interrupts that process. Remove the fading flower before seed forms and the plant receives a clear signal: the job is not done, so it had better make more flowers.

The result is not just tidier borders, although they do look better for it. Regular deadheading can add weeks, sometimes months, to the flowering season. Annuals such as cosmos and sweet peas will keep going until the first frosts if you stay on top of them, and many perennials will reward you with a second flush in late summer rather than a single show in June.

Getting the technique right

The mechanics are simple, but a little precision makes a real difference. Cut or pinch back to just above a healthy leaf node or side shoot rather than leaving a long bare stub of stalk. That stub will die back, look scruffy and give disease an easy way in. Keep a small pot or a trug with you so you are not dropping debris through the border, and work in the morning when stems are crisp and easy to snap.

• Cosmos and dahlias: snap or snip the faded head back to the next pair of leaves. On dahlias, look for the small bud sitting just below the dying flower and cut above it. With a bit of practice you will spot the difference between a bud and a seed head at a glance.
• Sweet peas: pick them constantly, even if you have no vase to fill. The moment a pod starts to swell, flowering slows sharply.
• Roses: cut back to a five-leaflet leaf that faces outward, which encourages an open, airy shape rather than a congested centre.
• Hardy geraniums: do not fiddle about with individual flowers. After the first flush, shear the whole clump back by a third and you will get fresh foliage and a second round of bloom.
• Spikes and spires: lupins, delphiniums and foxgloves should have the whole flowered stem cut back to the base as it fades, not just the tip. Some will throw up a smaller autumn spike in return.
• Petunias, pelargoniums and calibrachoa: pinch the soft stem between finger and thumb just behind the flower. Doing this also helps stop the plants going leggy in containers.

Annuals, perennials and what each needs from you

Annuals live their whole life in a single season. They germinate, flower, set seed and die, and they are genetically programmed to put everything into that seed. This is exactly why deadheading matters so much with bedding plants. Every bloom you remove buys you more flowering time before the plant decides its work is finished. Look at a basket of petunias in September: the ones that were never touched are usually a tangle of stems with a few tired flowers, while a regularly picked one is still going strong.

Perennials work to a different rhythm. They have roots and crowns to maintain, and their flowering window is naturally shorter. Deadheading still helps, often prompting a second, smaller flush in late summer, and it prevents the plant from investing in seed it does not need to produce. With plants such as nepeta, salvia and penstemon, a mid-season trim after the first flowers fade keeps them compact and productive well into autumn.

Plants that are better left alone

Not everything wants tidying. A garden that is stripped bare of every seed head by August is a poorer place for wildlife and less interesting in winter.

• Self-seeders: leave a few foxgloves, poppies, aquilegias or nigella to set seed and you will get free plants next year, often in places you would never have thought to plant them.
• Bird food: teasels, sunflowers, echinacea and rudbeckia provide valuable seed through the colder months.
• Winter structure: the flat brown heads of sedum, the papery globes of allium and the spiky skeletons of eryngium look wonderful rimed with frost.
• Anything you want to collect seed from: mark it now so you do not accidentally cut it later.

Making it part of the routine

Little and often beats a big tidy-up. Ten minutes with a cup of tea in hand, wandering the borders as you water in the evening, is enough to keep on top of most gardens. Containers, hanging baskets and the front of the border need attention every few days at the height of summer; herbaceous borders can wait a week or more.

Remember that deadheading only works if the plant has something in the tank. Keep watered in dry spells and feed containers weekly through the growing season, or you are simply asking a tired plant to do more with less.

Small mistakes that cost you flowers

• Leaving long stubs of stalk instead of cutting back to a leaf node or side shoot.
• Cutting into old, woody growth on shrubs rather than young flowering stems.
• Being too gentle with petunias and similar bedding. Pinch firmly, or the stem simply regrows the same tired tip.
• Tidying so thoroughly that there is nothing left for birds, bees and winter interest.
• Carrying on into September with perennials that need to harden off. Around the end of the month, stop deadheading and let them wind down for winter.