Spirea care guide: when & how to prune, fertilize and spray
Spiraea japonica (summer-blooming) · USDA zones 4–8
Compact summer-blooming shrub with pink flat-topped flowers. It flowers on new wood, so cut it back in late winter and shear after the first flush. (Spring-blooming bridal-wreath spireas are different: prune them after flowering.)
☀️ Sun
Full sun.
💧 Water
Moderate.
🪱 Soil
pH 6.0–7.0. Any well-drained soil. None needed.
How and when to prune spirea
Late-winter cut-back
When: 1–6 weeks before the last spring frost.
- zones 3–5: about Mar 29 – May 3
- zones 6–7: about Mar 4 – Apr 8
- zones 8–10: about Jan 14 – Feb 18
Summer spireas bloom on new growth, and a hard cut keeps them dense and mounded.
- Cut the whole plant back to 6–12 in (15–30 cm) above the ground, or by about half for larger plants.
- Remove dead stems at the base.
Tools: Hedge shears, Loppers
Shear after first flush for rebloom
When: 10–13 weeks after the last spring frost.
- zones 3–5: about Jul 19 – Aug 9
- zones 6–7: about Jun 24 – Jul 15
- zones 8–10: about May 6–27
Shearing off faded flower clusters triggers a second round of blooms.
- Lightly shear the top of the plant just below the spent flower heads.
Tools: Hedge shears
Fertilizing spirea
Spring feeding
When: from 1 week before to 3 weeks after the last spring frost.
- zones 3–5: about May 3–31
- zones 6–7: about Apr 8 – May 6
- zones 8–10: about Feb 18 – Mar 18
A single spring feeding as growth starts covers most shrubs for the year.
- Scatter fertilizer at the label rate from near the stems out past the drip line, where the feeder roots are.
- Water it in thoroughly.
What to use: 🌿 Balanced organic granular fertilizer (e.g. Espoma Plant-tone 5-3-3) · Slow-release balanced fertilizer (e.g. Osmocote Smart-Release 14-14-14)
Common spirea problems and how to fix them
Aphids
Signs: Clusters on new shoot tips.
What to do: Hose off, or use insecticidal soap.
Spirea care FAQ
When should I prune spirea?
Late-winter cut-back: 1–6 weeks before the last spring frost (around Mar 4 – Apr 8 in zones 6–7). Shear after first flush for rebloom: 10–13 weeks after the last spring frost (around Jun 24 – Jul 15 in zones 6–7). Compact summer-blooming shrub with pink flat-topped flowers. It flowers on new wood, so cut it back in late winter and shear after the first flush. (Spring-blooming bridal-wreath spireas are different: prune them after flowering.)
What is the best fertilizer for spirea?
A single spring feeding as growth starts covers most shrubs for the year. Good options: Balanced organic granular fertilizer (e.g. Espoma Plant-tone 5-3-3); Slow-release balanced fertilizer (e.g. Osmocote Smart-Release 14-14-14).
What soil does spirea need?
Any well-drained soil. Preferred pH 6.0–7.0. None needed.
How much sun and water does spirea need?
Sun: Full sun. Water: Moderate.
What are common spirea problems?
Aphids: Clusters on new shoot tips. Hose off, or use insecticidal soap.
More flowering shrubs care guides
Timings are given relative to your average frost dates, with examples for typical US climates. Always read and follow product labels.