UK pruning guide · RHS timing
When to prune greater duckweed 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 greater duckweed
Deadhead spent blooms; cut back leggy stems to a healthy bud or node.
Prune greater duckweed mainly to shape it and encourage more blooms. Deadhead spent flowers through the season, and carry out any harder structural pruning at the plant's dormant or post-flowering window to avoid cutting off the next round of buds.
More greater duckweed care for British gardens
Care at a glance
Pruning greater duckweed in the UK — FAQ
When should I prune greater duckweed in the UK?
Prune greater duckweed 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 greater duckweed in spring or summer in the UK?
There is no nesting-bird restriction that realistically applies to greater duckweed, 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 greater duckweed?
Deadhead spent blooms; cut back leggy stems to a healthy bud or node.
How often does greater duckweed need pruning in a British garden?
As needed through the season. Prune greater duckweed mainly to shape it and encourage more blooms. Deadhead spent flowers through the season, and carry out any harder structural pruning at the plant's dormant or post-flowering window to avoid cutting off the next round of buds.
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.