About
Hydrangea macrophylla 'Harrow's Blue' (L) is a reliable lacecap hydrangea to 1�2 m with pointed, dark-green leaves and domed clusters of flowers that vary from blue to pink according to soil pH. A popular and ornamental lacecap hydrangea for a sheltered, moist border.
About the genus
Hydrangea are deciduous or evergreen shrubs, or self-clinging climbers, with flowers in clusters usually comprising both small fertile and larger, showier sterile florets. They are grown for their dramatic and long-lasting flowerheads and often good autumn colour.
Growing conditions
SunlightFull sun, Partial shade
Soil typeClay, Loam, Sand
Soil pHAcid, Neutral
Soil moistureMoist but well-drained
AspectEast-facing, North-facing, South-facing, West-facing
ExposureSheltered
UK hardinessH5
Plant details
Plant typeClimber Wall Shrub
HabitClimbing
FoliageDeciduous
HeightHigher than 12 metres
Spread4-8 metres
Time to full height10-20 years
Suggested usesCity and courtyard gardens, Cottage and informal garden, Wildlife gardens
Native toJapan, S Korea
ToxicitySkin allergen. Wear gloves and other protective equipment when handling. Pets (dogs, cats): Harmful if eaten. For further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants
Care notes
CultivationGrow in any moist but well-drained soil in partial shade or grow in sun if soil remains reliably moist. Improve chalky soils with organic matter to support good growth. See climbing hydrangea cultivation
PruningPruning group 11 after flowering
PropagationPropagate by layering and softwood cuttings in early summer
Pest resistanceMay be susceptible to aphids, capsid bug, hydrangea scale and vine weevil
Disease resistanceMay be susceptible to a leaf spot, powdery mildews, grey moulds (Botrytis) and honey fungus (rarely)