Prune Perennials in Early Summer to Extend Flowering!
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What is the Chelsea chop? A new hairdo, dance craze, or fancy cut of meat? Nope, it’s just a pruning technique. By cutting back perennials in early summer, you can get better blooms, over a longer period, and stop your plants from becoming leggy! Here’s how it’s done.
The Chelsea Chop
The name “Chelsea chop” comes from the Brits because they do it around the time of the annual Chelsea Flower Show in May. However, for many areas, the timing is simply late spring or early summer. For me, it should be called the “4th of July chop,” since cutting the plants any later than that won’t give them enough time to recover and blossom before fall.
The whole idea is that one hour of pruning now would result in three more weeks of flowers at the end of their season! As well as extending the blooming season, you are controlling the growth and shape of your perennials for a better-looking, fuller, more compact plant. This pruning technique is especially suited to perennials that get too tall and leggy, such as phlox, aster, and sedum.
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It’s hard to chop, but it works, and you’ll be happy once you see the renewed blooms! I ruthlessly chop off the top 1/3 of 1/2 of the New England asters and tall phlox in my front flowerbeds because they get so tall we can’t see out of the windows! I am a little more selective in the other beds, cutting back only about half the plants in a clump, leaving a few to grow tall and blossom earlier. The shorter ones help to support the leggy ones, lessening the need for staking, and hiding their “naked ankles,” the leafless stems at the base of the taller plants.
I usually just use my trusty kitchen shears to make random sharp cuts but you can use pruners, loppers, or even hedge clippers to get the job done faster.
If you are as frugal as I am, save some of the cuttings to root and make new plants! New England asters and phlox cuttings placed in a glass of water will produce new roots in no time. They can be potted up to share or planted out in the garden, where they often bloom the first year.
The Chelsea chop is best done on late summer or fall bloomers like rudbeckias, helenium, goldenrod, asters, phlox, marguerites, chrysanthemums, and nepeta. Since it encourages branching, the plants will be shorter, more compact, and have more flowers. By leaving a few tall ones to bloom earlier, you can extend the bloom time. Give it a try!
→ Read more about growing a flower garden or caring for a perennial garden.
Robin Sweetser
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Should we do the "chop" on our leggy Dalias?
The best time to chop your dahlias to keep them from becoming too leggy is in late May or early June when they are 12-18 inches tall and have at least 2 sets of true leaves. Cut off half to a third of the height just above a leaf joint to encourage side branches. If you are doing it later, choose stems that aren’t flowering or only have a few buds so you don’t lose too many future flowers. Depending on your location you only have until the end of summer for the plants to rebound which is why timing is critical. If frost is not an issue in your zone go ahead and give them a haircut.
Is it also a good time to cut coneflower? Will they rebloom after a cut?
Hi Carol,
Sorry I did not see your question earlier when it would have been better to clip them back. Since it is getting close to their flowering time, you may want to wait and chop them next year in late May or June, but definitely before July 4th. It will encourage branching and give you more flowers. You can try cutting a few stems now just to see if they have enough time in your area to rebound with new growth and flower before cold weather sets in.
Would the Chelsea chop work on cup plants? I’m trying to find a way to keep them under 8’ tall, 😂
I have a New York Aster (which I believe is different from the New England Aster), that I planted last year. It is already blooming here in SW Ohio. Should I chop it as well? If so, should I wait until after all the buds have opened or do it now?
Can I cut the tops off my phlox before they have even flowered and they will still flower later?
Some of the earlier blooms on my newly set out hydrangea are turning brown. Should I cut those off and would that produce more blooms?
Where do you cut at to chop them back? Any certain way to do it?
