When to plant and prune Spiraea
Spiraea flowers from late June to late August and the dates below cover planting, flowering and the pruning window.
Planting, flowering and pruning by region
Spiraea is grown to the calendar rather than to the frost, so the same dates apply across the whole UK and every region below reads the same. Where a plant’s timings do follow the frost, Plot shifts them from the Midlands and Lowland Wales baseline using Met Office average frost dates.
| Where you are | Plant | In flower | Prune |
|---|---|---|---|
| South West Coast and Cornwall | early October to mid November | late June to late August | early March to late March |
| South Coast and Channel | early October to mid November | late June to late August | early March to late March |
| Greater London (Urban Heat Island) | early October to mid November | late June to late August | early March to late March |
| South East and Home Counties | early October to mid November | late June to late August | early March to late March |
| East Anglia | early October to mid November | late June to late August | early March to late March |
| Midlands and Lowland Wales | early October to mid November | late June to late August | early March to late March |
| Wales and West Coast | early October to mid November | late June to late August | early March to late March |
| Northern England | early October to mid November | late June to late August | early March to late March |
| Scotland Lowlands and Central Belt | early October to mid November | late June to late August | early March to late March |
| Scotland Highlands and Islands | early October to mid November | late June to late August | early March to late March |
| Northern Ireland | early October to mid November | late June to late August | early March to late March |
| Channel Islands and Isle of Man | early October to mid November | late June to late August | early March to late March |
Growing notes
Flat pink or crimson heads from midsummer onwards over often gold or bronze-flushed foliage, valuable because it flowers when most shrubs have finished. Compact, tolerant of hard pruning and easy in almost any soil. Shear off the faded heads to encourage a second flush.
At a glance
- Spacing
- 90 cm between plants
- Eventual height
- 120 cm
- Eventual spread
- 130 cm
- Hardiness
- H6
- Sun
- Full
- Frost tender
- No
- Grows in a container
- Yes, 30 litres or more
- Balcony rating
- 3 out of 5
Pruning: what to avoid
Spiraea genuinely splits in two. Summer-flowering Spiraea japonica flowers on the current year's growth and is cut back hard in early spring. Spring-flowering S. 'Arguta' and S. x cinerea 'Grefsheim' flower on last year's wood and must be pruned straight after flowering instead - prune those in spring and you lose the display.
Pruning group
RHS pruning group 6: S. japonica flowers at the tips of the current season's growth, so cut the whole plant back hard to a low framework in early to mid-spring as the buds swell
What usually goes wrong
- powdery mildew
Related guides
Timings cross-checked against RHS guidance for spiraea.