When to prune summer-flowering shrubs
Shrubs that bloom after mid-summer usually flower on the current season’s growth, so pruning in early to mid-spring allows time for the new growth to mature and flower in the same year. Avoid pruning in winter, as it may lead to frost damage of new shoots.
How to prune summer-flowering shrubs
Pruning requirements depend on the type of shrub, but all summer-flowering shrubs need routine removal of damaged, diseased or dead wood, as follows:
- Cut out any damaged or dead shoots back to their point of origin or to ground level.
- Where there are many stems remove some to ground level to keep the bush open and avoid congestion.
- Finally take out any weak, spindly or twiggy shoots right to the point of origin or to ground level so the plant concentrates its resources on strong new shoots that will bear the best flowers.
Then continue depending on the type of shrub. For convenience, we have divided summer-flowering shrubs into five groups on the basis of timing and type of pruning required:
1. Deciduous shrubs with flowers borne terminally on previous year's growth during mid- to late summer
- Examples: Lacecap and mophead hydrangeas.
- Pruning: In spring remove dead flower heads back to the first, or pair, of strong buds, and cut out to near ground level one in four of the oldest stems (to encourage new ones from the base).
2. Deciduous shrubs producing new flowering stems annually from a low branch framework
- Examples: Buddleja davidii, Caryopteris, Perovskia, Spiraea japonica.
- Pruning: In early spring cut back all stems to within three to four buds of older wood.
3. Evergreen shrubs flowering on current or previous year’s wood; flowers often of secondary importance to foliage effect
- Examples: Elaeagnus, Fatsia, hebes, Portugal laurel, rosemary.
- Pruning: No regular pruning, but in spring shorten or remove any vigorous or badly positioned growths.
4. Evergreen shrubs producing often numerous flowering shoots in late summer and autumn
- Examples: Calluna, Erica vagans, lavender, Santolina.
- Pruning: In spring cut back the flowered shoots to 1.5-2.5cm (½-1in) from older wood.
5. Wall-trained shrubs trained to form a permanent branch framework against a wall or fence
- Examples: Abutilon megapotamicum, Ceanothus, Fremontodendron.
- Pruning: In early spring cut back flowered shoots to two to four buds from the main framework branches. Pyracantha is pruned in late summer.
After pruning any shrub, mulch and feed.
Links
Shrubs: pruning evergreens
Shrubs: renovation
Mulching