It’s mid-May; beautiful blue skies, warm, sun-soaked days, heavy rain, freezing cold days and devious, late frosts. It has to be Chelsea Flower Show-time. The gathering of the horticultural glitterati, designer show-gardens to leave you breathless and a pavilion full to bursting with green stuff; now that’s an understatement if ever I’ve heard one. A horticultural heaven filled with a host of celestial, multi-coloured gorgeousness.
And talking of the ‘green stuff’, some of the plants in our gardens are ready for a (literal) slice of Chelsea action. It’s time for the Chelsea chop.
So what is the Chelsea chop?
The Chelsea chop is the name given to the process of ‘chopping’ (pruning) back by a third to a half, certain perennial plants in mid-May. The timing of this falls loosely around the middle of May, the time of the Chelsea Flower Show.
Why do we Chelsea chop?
The Chelsea chop has several benefits:
Removal of top growth at this time will delay flowering. But why on Earth might we want to postpone the much anticipated blooms of our favourite plants? And herein lies the rub. The Chelsea chop is NOT an imperative horticultural instruction. Gardening generally is all about the manipulation of nature. We prune to restrict size and/or promote improved flowering or fruiting, be it bigger, better and/or more bountiful. The Chelsea chop is just a further example of this manipulation.
Some perennials, like so many prepubescent teenagers, can shoot up and become tall and lanky. If not controlled (the plants that is, not the teenagers), top heavy growth can cause plants to flop, opening up the middle of the plant in a rather unattractive manner; I’m thinking certain drunken, red-faced celebrities falling out of taxis! The Chelsea chop, therefore, is an early-season prune which removes the top third to half of certain perennials, promoting the growth of side shoots lower down the stems. This, in turn allows for bushier, sturdier plants. The ‘chop’ whilst promoting new side-stem growth will delay the flowering of the plant. However, as the multitude of new side stems grow away, each will bear flowers, albeit slightly later in the seasons, and maybe slightly smaller.
How to do the Chelsea chop (see also video below)
There are a few ways to consider executing the Chelsea chop:
- Chopping all the stems on one plant will just delay flowering; more flowers, but later. What’s the point? As such, my recommendation is to chop HALF of the stems on each plant. This will allow non-chopped stems to flower as usual and the stems that have been chopped to flower a little later, thus prolonging the overall flowering period of the plant.
- Alternatively, if you have more than one of the plant to be chopped, e.g. you have three Hylotelephium ‘Herbstfreude’ (syn. Sedum ‘Autumn Joy’), chop ONE completely and leave TWO to flower as usual or chop TWO leaving ONE to flower as usual.
- Or finally, chop half of the stems on each of all three plants.
Which plants can be Chelsea chopped?
Plants that respond well to the Chelsea chop include:
Lavender
Penstemon
Nepeta
Achillea
Helenium
Anthemis
Echinacea
Phlox
Hylotelphium (formerly Sedum)
Asters & Symphyotrichum
Campanula
Rudbeckia
Helianthus
Coreopsis
MIKE THE GARDENER 