What is pinching out, and which plants need it?

Pinching out (or stopping) is removing the growing tip of a shoot, usually with finger and thumb. It is one of the highest-impact things a gardener can do for five seconds of work.

Why it works: apical dominance. The growing tip of a stem produces auxin, a hormone that travels down the stem and suppresses the side buds below it. This is why many plants grow as a single tall stem with little branching — the tip is chemically preventing competition.

Remove the tip and the auxin source goes with it. The suppressed side buds are released and begin growing, producing two or more shoots where there was one.

What that achieves:

Bushier plants with more stems.

More flowers, since most plants flower at shoot tips — more tips means more flowers, even though each may be slightly smaller.

Shorter, sturdier growth rather than tall and floppy.

Which plants to pinch:

Sweet peas — pinch at around 10cm, above the third or fourth pair of leaves. This is the single most valuable pinch in the garden and transforms the plant from one weak stem to several strong ones.

Cosmos, antirrhinums, petunias, fuchsias, coleus, dahlias and most bedding annuals.

Basil, repeatedly — pinch above a leaf pair whenever it reaches four or five pairs, and never strip individual leaves from the bottom, which is what kills supermarket basil.

Chrysanthemums, for a fuller plant.

Which plants to leave alone:

Anything grown for a single stem or bloom — exhibition dahlias and chrysanthemums are disbudded instead, which is the opposite technique.

Cordon tomatoes, where you remove side shoots and keep the leader — the reverse.

Plants with a single flowering spike — foxgloves, delphiniums, most bulbs.

Woody plants, which need pruning rather than pinching.

Timing: early, while growth is soft. Pinching a mature plant late achieves little and delays flowering.