UK pruning guide · RHS timing
When to prune begonia 'illumination salmon' 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 begonia 'illumination salmon'
Remove spent blooms at their stem base. To improve branching on trailing stems, pinch tips back to a node. In autumn, cut all top growth to within 5 cm (2 in) of the tuber and store the tuber dry.
Begonia 'Illumination Salmon' is a trailing tuberous begonia suited to hanging baskets. Deadhead spent flowers regularly to keep the long, cascading stems producing blooms. Pinch back excessively long trailing stems if desired to encourage branching. Cut back to the tuber in autumn as foliage fades. Otherwise pruning needs are light.
More begonia 'illumination salmon' care for British gardens
Care at a glance
Pruning begonia 'illumination salmon' in the UK — FAQ
When should I prune begonia 'illumination salmon' in the UK?
Prune begonia 'illumination salmon' 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 begonia 'illumination salmon' 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 begonia 'illumination salmon' 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 begonia 'illumination salmon'?
Remove spent blooms at their stem base. To improve branching on trailing stems, pinch tips back to a node. In autumn, cut all top growth to within 5 cm (2 in) of the tuber and store the tuber dry.
How often does begonia 'illumination salmon' need pruning in a British garden?
Deadhead weekly in season; annual cut-back at dormancy. Begonia 'Illumination Salmon' is a trailing tuberous begonia suited to hanging baskets. Deadhead spent flowers regularly to keep the long, cascading stems producing blooms. Pinch back excessively long trailing stems if desired to encourage branching. Cut back to the tuber in autumn as foliage fades. Otherwise pruning needs are light.
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.