I love pottering in the greenhouse and garden and listening to classic rock with my Labradoodle, Florrie.
Florrie the Labradoodle gets very excited when I say it is the time for the “Chelsea Chop”. I think she is expecting a barbecue in the garden with some meaty leftovers smothered in gravy. Sadly, she is going to be disappointed! There is no food involved, only secateurs. The “Chelsea Chop” is a pruning technique to help tall, multi-stemmed plants flower for longer in your garden.
This article will break down the pruning technique, its many benefits, and how you can best go about it to extend the flowering season of your perennials.
The “Chelsea Chop”
As spring progresses, the perennial plants in your garden start to flourish. These are the plants which grow back and flower year after year. Lying dormant all winter, green shoots can appear as early as February or March. Through April and May, they grow strongly as the soil warms up. Left unchecked, they could burst into flower in late June and early July. They look spectacular!
The problem is that after three or four weeks, the flowering season of some of your perennial plants is over. So you then spend the best months of summer looking at green leaves in your garden!
There is a solution you can try, though. Trimming back early growth in late spring can result in bushier, sturdier plants and more flowers. This is known as the “Chelsea Chop”, as the timing coincides with the RHS Chelsea Flower Show at the end of May.
It is rather heartbreaking though to cut back and lose all your early summer flowers in return for more later, especially when they are so close to their prime. However, there is a way where you can have your “jam today” and “jam tomorrow"—flowers in early summer and flowers in late summer.
Prolonging the Flowering Season
Tall, multi-stemmed perennials, such as the penstemons, can be encouraged to have a longer flowering season. Simply pinch out the top of about a third of the main stems before they flower. Use secateurs or your fingertips.
Choose stems from round the side or back of the plant. These will form multiple side shoots, which will in turn flower. So the “non-chopped” stems will flower early and the “chopped” stems will flower later. The overall result is flowers for longer!
Addionally, bees love penstemons. So they will be pleased with a constant supply of flowers to visit.
Plants to Chelsea Chop in this way include phlox, asters, lavender, sedum, helianthus, coneflowers and rudbeckia. Avoid chopping plants that flower just once, such as lilies, aquilegia and peonies. If you chop these, you won’t get any flowers until next year!
Make Plants Bushier and Sturdier
Another good reason to Chelsea Chop is to make plants bushier and sturdier. Some plants like sedums can quickly get leggy and flop over. Other plants can get too large and overshadow their neighbours. So the Chelsea Chop is a good way to keep your perennials in good shape.
Remember that the “choppings” make good material for cuttings. Sedums in particular take root quite quickly. Share them with your friends!
A Second Flush of Flowers
For some perennials such as hollyhocks, foxgloves and delphiniums, you can use the Chelsea Chop to get a second flush of flowers. Once the main flower spikes have finished and started to die back, then chop them off at the base. If you are lucky, more flower spikes will grow. Giving the plant a feed will increase your chances of success!
A Tidy Up
The final reason to Chelsea Chop is to give plants a tidy up. Hardy geraniums can look quite spectacular in late spring. Once the flowers have died back, the foliage starts to look quite tatty.
Chopping the whole plant back to the ground encourages new growth. Fresh green leaves soon appear, and the geranium starts to look healthy again.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
RTalloni on June 14, 2019:
Had not heard it called the Chelsea Chop before but pinching the central growth stem back for more blooms later is a hard thing to make one's self do. I have to say "it's worth it" 5 times before starting. ;)