UK pruning guide · RHS timing
When to prune green shiso 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 green shiso
Pinch the central growing tip between finger and thumb, removing the top 2–3 cm. Repeat on sideshoots as they elongate. Remove flower buds promptly at the base of the flower spike.
Green Shiso is an annual herb that needs regular pinching to delay flowering and keep leaves productive. Pinch out the growing tip once plants reach 20–25 cm to encourage branching. Pinch flower buds as soon as they appear — once plants bolt and set seed, leaf quality drops sharply and the plant dies.
More green shiso care for British gardens
Care at a glance
- When to prune shiso (perilla) in the UK — the species this cultivar belongs to
- When to prune green shiso in the UK — our other guide for the same plant
- General green shiso pruning guide
- RHS hardiness ratings explained
Pruning green shiso in the UK — FAQ
When should I prune green shiso in the UK?
Prune green shiso 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 green shiso in spring or summer in the UK?
There is no nesting-bird restriction that realistically applies to green shiso, since birds do not nest in it. The Wildlife and Countryside Act 1981 still protects any active nest you do find anywhere in the garden — the rule is about the nest, not the plant.
How do you prune green shiso?
Pinch the central growing tip between finger and thumb, removing the top 2–3 cm. Repeat on sideshoots as they elongate. Remove flower buds promptly at the base of the flower spike.
How often does green shiso need pruning in a British garden?
Every 1–2 weeks during the growing season. Green Shiso is an annual herb that needs regular pinching to delay flowering and keep leaves productive. Pinch out the growing tip once plants reach 20–25 cm to encourage branching. Pinch flower buds as soon as they appear — once plants bolt and set seed, leaf quality drops sharply and the plant dies.
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.