As May draws to a close and the RHS Chelsea Flower Show dazzles us with fresh ideas, it’s also the perfect time to try one of gardening’s best-kept secrets: the Chelsea Chop.
No, it’s not a new dance move or a trendy haircut—it’s a clever technique that helps control the size, shape, and flowering times of your herbaceous perennials. Named after the timing that coincides with the Chelsea Flower Show, the Chelsea Chop is typically done in the last week of May.
What Is the Chelsea Chop?
The Chelsea Chop involves cutting back certain perennials by about one-third to one-half. It may feel brutal, especially when your plants are already looking lush, but it encourages stronger growth, more compact plants, and in many cases, longer or staggered flowering.
Why Do It?
- Bushier Plants: Cutting encourages branching, which results in fuller, sturdier plants that are less likely to flop over.
- Delayed or Prolonged Flowering: Depending on the plant and how much you chop, you can delay blooms to stagger your garden’s display or extend the flowering period.
- More Manageable Size: Tall, leggy plants benefit from being kept in check, especially in small gardens or windy spots.
Which Plants Can Be Chelsea Chopped?
Here are some popular candidates:
- Sedum (now Hylotelephium): Prevents flopping and creates a tidy, dome-shaped plant. This is my favourite one to do as they can get very tall and flop over later in the season without support, Chelsea chopping them ensures their growth is restricted to avoid any flopping!
- Nepeta (Catmint): Encourages a second flush of flowers.
- Phlox paniculata: Staggered pruning leads to a longer blooming season.
- Heleniums and Rudbeckias: Delays flowering and encourages branching.
- Achillea (Yarrow): Promotes bushiness and stronger stems.
How to Do It
- Choose Your Moment: Late May is ideal, but early June is still fine in cooler areas.
- Assess Your Plant: Strong, healthy perennials are the best candidates. Avoid chopping newly planted or stressed plants.
- Make the Cut: Use sharp shears to cut back stems by one-third to one-half. You can chop the whole plant or just part of it for a staggered blooming effect.
- Water and Mulch: Give your plants a good drink and mulch around the base to reduce stress and keep moisture in.
Experiment and Observe
The Chelsea Chop isn’t an exact science, and different plants will respond differently. Some gardeners chop all stems evenly, while others do a “half-and-half” technique, cutting some stems and leaving others to bloom earlier. Keep a notebook or take photos to track what works best in your garden.
In Summary:
The Chelsea Chop is a simple, time-tested technique that can transform the look and performance of your summer garden. It’s not about hacking away recklessly—it’s about timing and encouraging your plants to put on their best show.
So grab your secateurs, channel your inner horticulturist, and give your garden a little Chelsea magic this May.
