What Is The Chelsea Chop: When To Chelsea Chop Prune

What Is The Chelsea Chop: When To Chelsea Chop Prune

By: Teo Spengler

What is the Chelsea chop? Even with three guesses, you might not get close. The Chelsea chop pruning method is a way to extend your perennial plants’ flower production and keep them looking neater to boot. Read on to learn more about the Chelsea chop pruning method and when to Chelsea chop prune.

Chelsea Chop Pruning Method

It’s named after that huge UK plant event – the Chelsea Flower Show – that takes place at the end of May. Just so, anyone wanting to try the Chelsea chop for plants should get the pruners out and ready as May comes to a close.

The Chelsea chop for plants involves cutting back by half the stems of tall perennials that bloom later in summer. Simply get out your pruners, sterilize them in a mixture of denatured alcohol and water, and clip back every stem.

The Chelsea chop pruning method removes all the buds on the top of the plant that would have opened relatively quickly. That means that the side shoots have an opportunity to branch out. Generally, the top buds produce hormones that inhibit the side shoots from growing and blooming.

Chopping off the top half of each stalk also means that the newly-shortened plant stems won’t get floppy as they blossom. You’ll get more blossoms, albeit smaller ones, and the plant will flower later in the season.

When to Chelsea Chop Prune?

If you want to know when to Chelsea chop prune, do it in the end of May. You may be able to do the same thing in June if you live in a more northerly area.

If you balk at the idea of cutting back all the shoots for fear of losing the current year’s flowers, cut them back selectively. For example, cut the front ones back but leave the back ones, so you’ll get quick flowers on last-year’s tall stalks, then later blossoms on this year’s shorter stalks in the front. Another option is to cut every third stem off by half. This works well with plants like sneezeweed or herbaceous phlox.

Plants Suitable for the Chelsea Chop

Not every plant does well with this pruning method. Species that bloom early in summer might not bloom at all if you chop them back. Some plants suitable for the Chelsea chop are:

  • Golden marguerite (Anthemis tinctoria syn. Cota tinctoria)
  • Purple coneflower (Echinacea purpurea)
  • Sneezeweed (Helenium)
  • Garden phlox (Phlox paniculata)
  • Goldenrod (Solidago)

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How To Give Plants The ‘Chelsea Chop’

The ‘Chelsea Chop’, so called because it’s normally done around the time of the annual Chelsea Flower Show, is a method of pruning herbaceous perennials to delay flowering by a few weeks.

It can be done on a wide range of perennials such as sedum, echinacea, monarda, aster, phlox, solidago, helenium and nepeta among many others.

The harder you cut back, the longer it will take the plant to re-grow and produce flowers. This pruning will also encourage the plant to produce side shoots and more compact growth, which means the plants will need less support. It also extends the flowering season by several weeks into early autumn.

The amount you cut back depends on how long you want to delay flowering and normally we cut the growth back by around half, but you can cut back by up to two-thirds.

To get maximum flowering where you have groups of perennials the pruning can be done in several stages, by leaving some clumps unpruned, some half pruned and other two-thirds. Where you only have a single clump of each type of perennial you can cut back half the clump or trim back every other stem so that the clump will produce flowering stems at different times.

Results vary on the growing season, but it’s worth experimenting with to extend the flowering season.

Chelsea chop
The Chelsea chop (so called because it is usually carried out at the end of May, coinciding with the RHS Chelsea Flower Show) is a useful technique that helps control the size, shape and flowering time of certain summer-flowering plants. Late May or early June is the perfect time to do it.

Plants that respond well to the Chelsea chop include:

Echinacea purpurea
Phlox paniculata

Many other summer and autumn-flowering perennials can be treated similarly. The degree of cutting back is specific to each species but the closer to flowering time you prune, the greater the delay in flowering. Doing the ‘Chelsea chop’ can delay the flowering of perennials by four to six weeks. You can either prune all the stems on a clump, which delays all the flowers, or just half of them, which spreads the plant’s flowering over a longer period. This can have some positive results:

The plants are not so tall and leggy
They need less staking
The flowers are smaller but more numerous

This happens because the removal of the top shoots enables the side shoots to branch out (the top shoots would normally inhibit the side shoots by producing hormones in a process called apical dominance). Using this method, along with regular feeding and watering, ensures beds and borders look tidy throughout summer.

To carry out the Chelsea chop:

Use sharp, clean secateurs to cut back the stems of perennials by one third or a half, making a sloping cut just above a leaf joint.
If you have several clumps of one plant, try cutting back a few, but leaving others. This will prolong the overall flowering time
Another method is to cut half the stems back at the front of the clump which will extend the season of flowering rather than delay it.

Here’s an example of a Phlox paniculata that I cut back half of the foliage in late May this year:

Phlox paniculata prior to carrying out the Chelsea chop

Phlox paniculata after carrying out the Chelsea chop

Phlox paniculata cut stems after carrying out the Chelsea chop

What is the Chelsea Chop?

The Chelsea Chop is a pruning method that will delay flowering in summer perennials and create more compact plants. By cutting back all or part of the plant you can get plants that flower longer and later into the year. Doing the Chelsea Chop for Rozanne® and other perennials will allow her to flower later and for a longer season.

When Should I Chop?

The Chelsea Chop gets its name from the RHS Chelsea Flower Show , which happens in late May, early June and is when the Chelsea Chop should be carried out in your garden. You can also take your shears to some perennials in July to encourage a second wind of flowering.

Easy How-To

There are two ways to carry out the Chelsea Chop, depending on your courage, and the look you want to achieve. You can cut the entire plant back, or you can trim one-half to one-third of the stems.

Trimming the entire plant will create a more compact plant that will produce more flowers later into the year. To chop this way, simply grab your shears and begin chopping. Cut off about one-third to one-half of the plant.

For plants with multiple stems, or if you want to create a staggering flowering look, chop some stems off the plant and leave others. The part that hasn’t been chopped will flower first and then the chopped part will flower later, prolonging your flowering season.

More Resources

You can do the Chelsea Chop on certain plants to get new foliage and others to get a second flush of flowers. Doing the Chelsea Chop can also help keep taller plants shorter and less likely to grow unruly and fall over.

If you’re a little hesitant to chop away at your lovely plants, there are other seasonal pruning methods you can use to keep your blooms lush and healthy.

How brave are you with your secateurs? Have you tried the Chelsea Chop?

What is the Chelsea Chop? A new hairdo or a fancy cut of meat? Nope, it’s just a pruning technique borrowed from the Brits. By cutting back leggy perennials by early summer, you will have more flowers on a fuller-looking plant. It’s hard to chop but it works and you’ll be happy once you see the renewed blooms! Here’s how.

The name “Chelsea Chop” comes from Great Britain 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” because 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 to get too tall and leggy such as phlox, aster, and sedum.

Photo: Time for the Chelsea chop otherwise these plants get too tall and floppy.

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 hide their “naked ankles”, the leafless stems at the base of the taller plants.

Before: The rapidly growing asters and phlox have obscured the dark-leaved ligularia.

After: Now the ligularia has a fighting chance. I left a few tall asters near the back of the bed to blossom earlier than the newly cut plants in front.

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.

Before: Phlox take over in front of the shed and get so tall and floppy it can be a challenge to open the door! They also overtake the other plantings.

After: Now you can see the container that was hidden by the growing phlox plants. I left a row of tall ones in the back to blossom first. They have the shed to lean on for support and the shorter plants in front of them will hide their naked ankles.

Pink asters are in short supply in my garden so I take advantage of the opportunity to make more.

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!

The Chelsea Chop: plants

There are certain plants that respond well to the Chelsea chop. These are.

  • Anthemis tinctoria
  • Echinacea purpurea
  • Helenium
  • Phlox paniculata
  • Sedum (upright, strong-growing forms such as 'Herbstfreude')
  • Solidago (Goldenrods)

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Garden Art

Garden art, such as this glass can draw the eye away from less-than-perfect planting

A good technique that works well for me at Driftwood, bearing in mind that I have a eclectic collection of bits and pieces around the garden, both metal and ceramic. If a corner or area starts to look less impressive as plants go over, I tend to move objects around to ensure the eye is drawn to the art or object rather than the less than perfect planting around it. A good example is the beautiful ceramic hydrangea which can quickly fill a gloomy, shady corner when needed. I’ve also used these stained glass panels that I bought in a junk shop a few years ago. I had a local artist make the frames for them and set them on stakes, they are perfect for brightening up a hedge or border. Trust me it works a treat!

If you’d like to learn more about Geoff’s award winning garden, visit his website, or better still make sure you visit on one of his open days this summer.

Geoff Stonebanks

Geoff Stonebanks lives in Bishopstone, near Seaford in East Sussex and spends all his time gardening and fundraising for Macmillan Cancer Support. Using his multi award-winning garden - Driftwood - he has raised over £137,600 for various charities in 11 years, £85,000 of that for Macmillan. The garden, which first opened to the public in 2009 has featured on BBC2 Gardeners' World, Good Morning Britain and in many national and local media publications. In his spare time, Geoff is also an Assistant County Organiser & Publicity Officer in East & Mid Sussex for the National Garden Scheme.

Watch the video: The Chelsea chop