The Chelsea Chop – What Is It, How & When To Do It


If you’ve ever had flowers that were growing so well in the early to mid-season, only to begin to lean or flop over by mid to late summer, then you may be able to fix them with the Chelsea Chop. I’ve grown to love this method as it allows me to landscape with certain native plants that can be difficult to grow in formal flower beds.

What is the Chelsea Chop?

The “Chelsea Chop” is a pruning method where you cut back taller perennials in Spring by one-half to one-third of their height. The result is stronger and sturdier stems as well as a more compact plant. It will help prevent certain perennials from leaning, flopping, or tipping over and provide an overall nicer appearance.

Although this is a standard pruning method, the name ‘Chelsea Chop’ originated in England. It comes from the Chelsea Flower Show, which coincides when a gardener should prune their perennials in England’s climate.

I’ve successfully used this method on many of my Native Plants as well as other common perennials. When certain plants are grown in formal flower beds and spaced apart, it is a necessary chore to keep them erect and provide a nice, tidy appearance throughout the growing season.

In this article:

How to do the Chelsea Chop

There are 2 primary methods for doing the Chelsea Chop. Each one has a specific purpose. But, if your main concern is to prevent a plant from flopping over, then you should focus one method 1, the straight cut.

1 – Straight Cut

To perform the Chelsea Chop, simply cut back a perennial flower by 1/3-1/2 of the height. If you are concerned with the plant leaning/flopping, cut the entire plant back by half.

The above photos are of the Chelsea Chop performed on False Sunflower, Heliopsis helianthoides

Do not overthink this method. It is very straight forward, and doesn’t require any special measurements. Just grab a bundle of flowers or get a large pair of sheers, and cut.

2 – Cascading ‘Chelsea Chop’

If you are trying to prolong blooming, but want to create a layered look that also reduces flopping, then you should try the cascading Chelsea Chop. To do this, simply trim the front-most row of flowers by 1/2 the height. If you are ambitious, you can repeat this again on the next row and trim them by 1/3 the height. This operation will allow the front, trimmed rows of flowers to helps support the rear rows, while also prolonging the bloom time.

For an example of this, see the video clip below where I perform this exact operation to show how I can reduce my Coreopsis from encroaching on my sidewalk, while creating a somewhat layered look at the same time.

Why you should Chelsea Chop tall perennials

Tall flowering perennial flowers can sometimes grow too many flowers for their stalks to support. When this occurs, the flowers will arch or lean down to the ground. This can happen for a variety of reasons, from too fertile soil, not enough competition, or even irregular sunlight.

But the best way to avoid it is to perform the Chelsea Chop. Doing so will result in a shorter plant, which will result in less ‘torque’ or leverage on the stem. Thus, the flower will still flower nicely, but be standing tall and erect.

Look at the two photos below. These pictures are of the same flower bed. In 2021, I did not perform a Chelsea Chop. In 2022, I did. The effect and aesthetic benefit is patently obvious.

When to do the Chelsea Chop

The best time to do the Chelsea Chop is about 4-6 weeks before blooming, or when the plant has reached 1/2-2/3 of it’s expected overall height. For most plants, this is between mid-Spring and the start of Summer. But could be earlier or later depending on the species.

For example, Echinacea should be cut back by early June, while New England Aster can be cut back by early July. Or, if you Echinacea plant reaches 30″, then trim it back to 15-20″ tall.

List of 32 plants that you can ‘Chelsea Chop’

The following list of plants respond well to the Chelsea Chop. If you have designed your flowerbeds to where these plants receive irregular sunlight, or sun from one direction only, then it may be a good idea to perform the Chelsea Chop to keep the bed looking neat and tidy. I have often done this on taller Asters such as New England Aster or Smooth Blue Aster (deer assisted!), as well as Ratibida and False Sunflower (Helianthus Helianthoides).

But, I have witness it work on many of my native plants that have been ‘trimmed’ by deer such as Joe Pye Weed, other perennial Helianthus and even Tall Coreopsis.

  1. Agastache (Anise Hyssop)
  2. Achillea (Yarrow)
  3. Amsonia (Blue Star)
  4. Anthemis tinctoria
  5. Artemisia
  6. Asters (Symphyotrichum genus)
  7. Bee Balm
  8. Bellflower (Campanulas)
  9. Boltonia asteroides
  10. Cranebill
  11. Dendranthema grandiflora (Chrysanthemum)
  12. Echinacea purpurea (Coneflower)
  13. Eupatorium (Joe Pye Weed)
  14. Helianthus (Perennials types only)
  15. Helenium (Sneezeweed)
  16. Heliopsis
  17. Hylotelephium, (or other tall Sedum plants)
  18. Ironweed (Vernonia)
  19. Kalimeris
  20. Lavender
  21. Monarda
  22. Montauk daisy
  23. Nepeta (Cat Mint)
  24. Phlox
  25. Penstemon (Beardtongues)
  26. Ratibida pinnata (Prairie Coneflower)
  27. Rudbeckia hirta (Black Eyed Susan)
  28. Rudbeckia triloba (Brown Eyed Susan)
  29. Shasta Daisy
  30. Tall Coreopsis
  31. Tansy
  32. Toad Lily
  33. Veronicastrum (Culver’s Root)
  34. Wild Bergamot

Final Thoughts

The Chelsea Chop is a good strategy to be able to garden with certain flowers that can have a tendency to lean or flop over. By reducing the overall height earlier in the season, we can strengthen the bottom stalks with minimal impact to the final showiness of the flowers. It is a great, safe way to help keep a beautiful formal flower bed looking great.

Read More Gardening Tips Here

References:

[1] – Yemm, Helen. RHS Grow Your Own Flowers. London:Mitchel Beazley. 2010, pp.42-43

[2] – Griffin, Althea R. Perennials … What you need to know! : Tips and advice to grow tried and true perennials, Plant it Pub., 2011, pp 12,21,41,56,86,95-97,

Joe Foster

Hi - I grew up outdoors in nature - hiking, fishing, hunting. In high school I got my first job at a garden center where I learned to garden and landscape. I've been growing plants from seed and designing native plant gardens for over 10 years. I hope to share some of my knowledge with you! You may have seen some of my videos I create on our YouTube channel, GrowitBuildit (more than 10 million views!). You can find my channel here: https://youtube.com/@growitbuildit Additionally I am a wood worker / DIY enthusiast. I enjoy designing/building projects (with hand tools when I can!). I hope to give you some tips and useful information!

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