Why deadheading pays you back in flowers

A plant's whole purpose in life is to make seed. Once a flower has been pollinated and begins to set seed, the plant switches its priorities: growth slows, new buds stop forming, and everything is channelled into swelling pods or hips. Deadheading interrupts that process. By removing the fading flower before seed develops, you persuade the plant into another round of flowering as it tries again to reproduce. Do it regularly and you effectively trick a plant into blooming for months rather than weeks.

The other benefit is tidiness. A border quickly becomes shabby if spent blooms are left to brown and flop. Regular snipping keeps the display looking fresh, and it lets you see what is actually doing well. It is one of the cheapest, most effective jobs in the garden — a few minutes with a pair of scissors can double the flowering season of a dahlias bed or a hanging basket.

Which plants respond best

Almost any repeat-flowering plant will benefit, but some respond dramatically:

• Dahlias — relentless performers. Cut flowers for the vase all summer and they will keep producing more.
• Roses — bush, shrub and repeat-flowering climbers will give a second and third flush with consistent deadheading.
• Sweet peas — pick or snip every day or two. Leave one pod to form and flowering can stop within a fortnight.
• Cosmos, calendula, zinnias and petunias — annuals that will flower until the first frost if kept seed-free.
• Penstemons, lupins and delphiniums — cut the whole flowered stem back to a strong shoot or leaf and many will send up fresh spikes.
• Hardy geraniums — shearing an entire clump back after its first flush often triggers a second, neater one.

Some plants are best left alone. If you want rose hips for winter colour and birds, teasels and echinacea for goldfinches, or alliums and honesty for their architectural seedheads, leave them standing. Self-sowers such as nigella, poppies, calendula and foxgloves need to set seed if you want them to reappear next year, so deadhead only part of the patch and let the rest run to seed.

How to do it properly

The principle is simple: take the flower and its stalk, but don't leave a bare stub. Snip or pinch just above a strong leaf, bud or side shoot so the plant has somewhere to grow from.

For roses, follow the stem down to the first leaf with five leaflets and cut about a centimetre above it, choosing an outward-facing bud where you can see one. This keeps the centre of the bush open. For dahlias, trace the faded flower down to the next pair of leaves and cut there — cutting higher leaves an unsightly stalk, cutting lower removes potential flowering shoots.

For spikes like delphiniums, lupins and penstemons, either nip out individual faded florets as they pass or, once the spike is finished, cut the whole thing back to a fresh shoot lower down. For single blooms on petunias, pelargoniums and cosmos, snap or snip the flower with its short stalk — the seed pod sits at the base, so removing just the petals is not enough.

Finger and thumb work well for soft-stemmed plants such as sweet peas and petunias, but sharp scissors or snips are quicker and cleaner on anything woody or sappy. Clean cuts heal fast and don't tug at the plant.

Timing, tools and a few useful habits

Little and often beats a fortnightly blitz. In peak season, walk the garden with a bucket and snips every couple of days — sweet peas and dahlias really do need near-daily attention. Do it in the morning while it's cool, when plants are turgid and the job is pleasant rather than a chore.

• Carry a small bucket or trug and a pair of sharp snips or florist's scissors.
• Wipe blades with a dab of methylated spirit between plants if you have been cutting anything with black spot or mildew.
• Compost healthy material, but bin diseased foliage rather than adding it to the heap.
• Bring the best of the cut stems indoors — dahlias, sweet peas and cosmos make excellent vase flowers, and cutting is deadheading.
• Keep on top of it after rain, when spent petals cling and disease gets a foothold.

When to stop

As summer turns to autumn, ease off. Leaving the last flowers to set seed gives birds a food source and gives you hips, seedheads and structure to carry the border through winter. It also lets self-sowers scatter for next year. Stop feeding and deadheading around the end of September, let the plants wind down naturally, and pick up the snips again when the first buds open next spring.