Pinching or cutting back perennials is a task that will result in a nicer appearance in the garden. A plant that has been pinched often is short, stockier and less likely to flop over in the garden. The most common plant pinched or cut back is the garden mum, but other plants respond well to this treatment.
Pinching is the removal of the growing point of the stem, resulting in the development of side shoots. By pinching, one growing shoot will produce two, four or more side shoots each. This increases the total number of flowers and the visual impact.
Some plants should only be cut back once, while others can be pinched a couple of times. The classic example is garden mums. When the mum reaches about 6 inches high cut it back to about 3 inches. A month later when the plant reaches 6 to 8 inches again, cut it back again to 4 or so inches. This process can be repeated until July 1. Growth produced after this period of time will need to develop for fall flowering. Fall asters can also be treated this way.
There are several other garden perennials that benefit from a one-time pinching or cutting back. Cutting them back by about half will reduce the height of the plant which in turn helps to develop a shorter, stockier plant. The result is a more manageable plant that stands up and produces a plethora of flowers.
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Perennials that respond well to pinching include:
▪ Sedum (Autumn Joy)
▪ Solidago (Goldenrod)
▪ Platycodon (Balloon Flower)
▪ Eupatorium (Joe Pye Weed)
▪ Nepeta (Catmint)
▪ Russian Sage
Pinching can be done one stem at a time, or for thick plants, a pair of hedge shears may work. Hand-pruning one at a time leaves the plant in better condition as the placement of the cut can be controlled.
Make the cut just above a leaf. The new shoot will develop from the axial of the leaf. Give it a try and hopefully you will find your garden a little more manageable this season.
While pinching works well on some plants, do not go crazy as some plants will not tolerate this removal of the dominant stem. Examples would be perennials that produce only one dominate stem such as hosta, daylilies, coral bells and dianthus to name a few. Before pinching think about the growth habit and how the plant produces flowers.