THE CHELSEA CHOP | A haircut for your perennials

Fellow gardening friends: it’s time. Time for the Chelsea Chop.

It’s the English gardener’s miracle cure, the secret to a long flowering period, and the way to get compact, bushy plants. So, grab your clippers and read on.

The Chelsea Chop is a pruning method for some herbaceous plants at the end of May/beginning of June – around the time of the legendary Chelsea Flower Show in London.

It makes herbaceous plants, like phlox and stonecrop, grow much bushier and seriously extends their flowering period. Depending on the plant, this could be by a whopping four to six weeks of more blooms.

Especially plants like catnip and stonecrop (sedum), which will usually have fallen apart by the end of summer, stay upright instead of sporting gaping gaps all over the place.

Phlox with an extended flowering period

The Chelsea Chop – so how does it work?

Let’s stick with phlox as an example.

You don’t want to cut the whole phlox. It would be possible and would make the plant much more compact, but you’d lose out on that long flowering period, which – for me – is the primary benefit.

Instead, pick a selection (around 25% to 50%) of the shoots and chop them back by about a third. Of course, that won’t extend the flowering period of individual flowers, but since the shoots you’ve cut will flower later than the ones you haven’t touched, the overall flowering period of the plant will be longer.

Cutting back the whole plant will delay the entire flowering period, which could be an advantage in terms of your flowerbed composition if you’re looking to create a synchronized bloom with other plants that flower later in the year.

Performing the Chelsea Chop on phlox

Where you’ve cut, the phlox will develop new shoots, and on these, new buds will form. That means that not only will your plant become bushier and more sturdy, but – here’s the trick – you’ll also get a delayed second bloom. Then, when the first flowering period is almost over on the shoots you haven’t cut, the buds will start to open on the newly sprouted stems. Tadah!

I usually take the largest and longest shoots and, of those, I only take every other one. It makes it less noticeable and your plant still flowers regularly.

I know it’s hard to be this severe with your beloved, freshly-sprouted plant babies, especially when they’ve already grown nice and tall, but it’s so worth it. Last year, I purposely didn’t chop a few of my plants for the sake of comparison, and you could really see the difference. The Chelsea chop even does an excellent job of stopping your stonecrop from getting too heavy and falling apart, as it often tends to do.

Give your plants a nice glug of water afterwards, throw on a little fertilizer, and you’re done.

Oh, and one more thing: you can always try growing new plants from the cuttings. This works particularly well with stonecrop. Just place the cut shoots in a vase, and you won't have to wait long for new roots to start growing.

But: I’d recommend that you go easy on the Chelsea Chop the first time around.

Maybe try it out on just a few shoots to start with. Especially if you’ve had a particularly dry spring, pruning your plants too radically could cause damage rather than abundant flowering.

Timing is also crucial.

And please look through the following list before you get clipper-happy. It doesn’t work with all flowers – some examples of that are peonies, columbine and hydrangeas.

Performing the Chelsea chop on stonecrop

Here’s a list of plants you can use the Chelsea Chop on:

Phlox

Catnip

American asters (Symphyotrichum)

Scarlet beebalm

Yarrow

Purple coneflower

Wallflower and wallflower "Bowles Mauve"

Golden marguerite

Shasta daisy

Stonecrop (Sedum)

Sneeze weeds

Rudbeckia

Sunflowers (Helianthus – the perennial kind, not the annual one)

Goldenrod

Don’t confuse this with “normal” pruning, though, which takes place AFTER the flowering period has finished and is meant to promote a second round of flowering.

That’s recommended for plants including:

Delphiniums (Larkspur)

Foxgloves

Wolf’s bane

Common hollyhock

Astrantia

Beardtongues

Lupines

Knapweeds

Mullein

And then there are those plants that don’t look quite so great when they’ve finished flowering. For those, I’d recommend pruning them right back (after they’ve finished flowering) to allow beautiful, new leaves to grow:

Lady’s mantle (sometimes the odd little flower will make an appearance)

Certain types of crane’s bill, if the leaves start to look shabby

Woodland sage

Will you try it? Or have you tried it before? Did it work for you? Let me know!

Love from the Cottage Garden!