Hydrangea (Mophead & Lacecap)
Hydrangea macrophylla
Pruning Window: Mid to Late Spring (after frost risk has passed, March/April)
Pruning Group: RHS Pruning Group 1 (Flowers on Old Wood)
Crucial rule: leave old faded flower heads on the plant all winter to shield the tender emergent buds from severe frost.
Step by Step
- Leave flower heads on through winter: The papery dried blooms protect spring buds from windchill and frost.
- Spring Head-removal: In late March/April, cut back each stem just above the first pair of healthy, plump green buds beneath the faded flowerhead.
- Rejuvenation: On established bushes over 3 years old, cut 1 or 2 of the oldest, thickest stems right down to the ground level to stimulate fresh basal canes.
- Acid/Alkaline Soil note: Soil pH affects flower colour (blue in acidic ericaceous soil with aluminium, pink in alkaline lime soil).
Tools Required
Bypass secateurs, Spring mulch
RHS (UK) Notes
RHS H5. Thrives in sheltered borders and moist humus-rich UK woodland soils.
USDA (US) Notes
USDA Zones 5–9. Protect with burlap in northern zones experiencing sub-zero freeze cycles.