Pruning is an important part of maintaining many different kinds of annual or perennial flowers. Pinching is a form of pruning that is useful for encouraging a full, bushy plant. When a gardener pinches back a flower, the process is as the name suggests–she uses the thumb and forefinger to pick off tender terminal growth from all over the plant. The terminal growth is the topmost growth at the ends of the stems. When gardeners pinch plants back, plants respond by sending forth new lateral growth that fills the plant out on the sides and makes it more attractive.
Place your thumb and forefinger on the stems at the point where the first set of leaves is growing. This point is a “node.”
Pinch the stem firmly between your thumb and forefinger to sever it.
Repeat steps 1 and 2 over the entire plant to make it even and reduce the entire size of the plant evenly.