The ‘Chelsea Chop’ is a useful trick designed to extend the flowering season of herbaceous plants which is carried out around the time of the Chelsea Flower Show in May – hence the name. It’s too late for that now, however, you can rejuvenate any tired July borders by employing the ‘Hampton Hack’, a method that happens to coincide with the Hampton Court Palace Garden Festival.
Shrubs that respond well to the Hampton hack include:
These can all take quite tough mid-summer pruning which will prolong their life and stop them from becoming unattractively untidy or too big for their boots.
The degree of cutting back is specific to each species but the closer to flowering time you prune, the greater the delay in flowering. Doing the ‘Hampton Hack’ can delay the flowering of perennials by four to six weeks. You can either prune all the stems on a clump, which delays all the flowers, or just half of them, which spreads the plant’s flowering over a longer period. This can have some positive results:
The plants are not so tall and leggy
They need less staking
The flowers are smaller but more numerous
This happens because the removal of the top shoots enables the side shoots to branch out (the top shoots would normally inhibit the side shoots by producing hormones in a process called apical dominance). Using this method, along with regular feeding and watering, ensures beds and borders look tidy throughout summer.
After Lupins and Delphiniums have finished flowering, chop them down to about 30 cm in height, apply a mulch around their base and give them a generous drink of water. They’ll start into growth again and may produce additional smaller flowers on shorter stems later on in the year and you’ll have new foliage to look at instead of a yellowing mess.