UK pruning guide · RHS timing
When to prune nepeta 'six hills giant' in the UK
Why the timing differs here
For shrubs that flower on the current season's growth, the RHS times pruning to early or mid spring — after severe weather has passed and once the growth buds begin to swell. In Britain that is usually March into April rather than the February common in warmer regions; prune too early and the new shoots meet a late frost.
How to prune nepeta 'six hills giant'
After the first flowering flush, shear the mound back to 10–15 cm above ground level using hand shears. New growth will push quickly and a second flush of lavender-blue flowers follows in late summer. In early spring, cut any remaining old stems to near ground level.
Nepeta 'Six Hills Giant' responds well to being cut back hard after the first flowering flush to produce a vigorous second flush later in summer. Shear the whole plant to about 10 cm after the main June flush fades. A final cut-back in early spring tidies the plant before new growth begins.
More nepeta 'six hills giant' care for British gardens
Care at a glance
Pruning nepeta 'six hills giant' in the UK — FAQ
When should I prune nepeta 'six hills giant' in the UK?
Prune nepeta 'six hills giant' in early to mid spring. For shrubs that flower on the current season's growth, the RHS times pruning to early or mid spring — after severe weather has passed and once the growth buds begin to swell. In Britain that is usually March into April rather than the February common in warmer regions; prune too early and the new shoots meet a late frost.
Is it illegal to prune nepeta 'six hills giant' in spring or summer in the UK?
Pruning itself is not illegal, but destroying an active nest is. Under the Wildlife and Countryside Act 1981 it is a criminal offence to damage or destroy the nest of any wild bird while it is being built or in use, and the RHS treats the nesting season as March to August, sometimes longer. Check nepeta 'six hills giant' for nests before cutting, and if you find an active one, leave that part of the plant until the birds have fledged.
How do you prune nepeta 'six hills giant'?
After the first flowering flush, shear the mound back to 10–15 cm above ground level using hand shears. New growth will push quickly and a second flush of lavender-blue flowers follows in late summer. In early spring, cut any remaining old stems to near ground level.
How often does nepeta 'six hills giant' need pruning in a British garden?
Twice yearly: mid-summer shear plus early spring cut-back. Nepeta 'Six Hills Giant' responds well to being cut back hard after the first flowering flush to produce a vigorous second flush later in summer. Shear the whole plant to about 10 cm after the main June flush fades. A final cut-back in early spring tidies the plant before new growth begins.
Why is UK pruning timing different from American advice?
Most pruning guides online are written for US conditions and anchored to USDA zones. Britain's maritime climate gives milder winters but later, less predictable last frosts — from March in the south-west to mid-May in the north — so the RHS advises against winter pruning for most plants: it pushes out soft growth that a late frost then kills. Britain also has the nesting-bird law, which has no US equivalent.