THE CHELSEA CHOP | Bring those plants in line

Ladies and gentlemen: 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 certain herbaceous plants that you carry out at the end of May/beginning of June – around the time of the legendary Chelsea Flower Show.

It makes herbaceous plants, like phlox and stonecrop, grow much bushier and significantly extends their flowering periods. 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 the summer, stay upright instead of sporting gaping gaps all over the place.

Phlox with an extended flowering period

The Chelsea Chop – how does it work?

Let’s stick with phlox as an example.

You don’t want to cut the whole phlox (which 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 percent) 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

In the places 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 these, I only take every other one. That way, it’s not too noticeable, and the plant still flowers regularly.

I know it’s hard to be this strict 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 afterward, 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. Simply place the cut shoots in a vase, and soon you’ll see new roots start to grow.

But: I’d recommend that you go easy on the Chelsea Chop 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 exuberant flowering.

Timing is also crucial.

And please look through the following list before you get clipper happy. It doesn’t work with all flowers – for example: 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?

Love from the Cottage Garden,

Sarah