It’s Time for the Chelsea Chop

Sonia Uyterhoeven is Gardener for Public Education at The New York Botanical Garden. Join her each weekend for home gardening demonstrations on a variety of topics in the Home Gardening Center.

For those of you who grow sweet peas from seed, you will know from experience that once the seedlings reach 4–6 inches tall, you need to pinch them back to approximately half their height to encourage good branching. Some people pinch just once, other pinch twice— like most things in gardening, method is often based on personal preference.

If pinching seedlings with your fingertips sounds too dainty, then just wait until late May or early June, the time to grab your sheers or pruners and try them out in the garden on a larger and more satisfying scale…but not on your sweet peas, please.

In England they call cutting back perennials the “Chelsea Chop.” This is because the time for cutting back perennials lands on the same week of the famous Chelsea Flower show (the third week of May). Cutting back some (not all) perennials early in the season encourages lateral growth and produces nice and bushy (if not slightly shorter) plants.

What are some candidates for this treatment?
Sedums (Sedum), pictured: Chop them in half in late May and you will prevent them from opening up and falling over later in the season.
Montauk daisies (Nipponanthemum): They often relish being chopped twice in the season, which keeps them from splitting open once they are in bloom.
Asters (Aster) and chrysanthemums (Chrysanthemum): If you are meticulous and have just a few, you can pinch them by hand by taking your thumb and forefinger and pinching off the growing tip of the plant (generally a half inch to 2 inches from the top). Let the plant grow a couple weeks until it puts on 2 or 3 nodes and then pinch again. For those of you who are as impatient as I am, just chop them in half once and then walk away. read more »