Hydrangea macrophylla /haɪˈdɹeɪnd͡ʒə/
Common name: Bigleaf hydrangea · Mophead hydrangea · French hydrangea
Hydrangea macrophylla is a deciduous shrub in the family Hydrangeaceae, native to Japan and Korea. It typically grows 1–2 m tall with large, serrated, ovate leaves and showy summer flower heads in rounded "mophead" or flat "lacecap" forms. Its flower color famously shifts between pink and blue depending on soil acidity and aluminum availability. It is one of the most widely grown ornamental shrubs in temperate gardens worldwide.
Care summary
Sun
Partial shade; morning sun, afternoon shade ideal
Water
Keep soil consistently moist; wilts quickly in drought
Soil
Rich, moist, well-drained; pH affects flower color
Hardiness
Zones 6–9
Mature height
About 100–200 cm (3–7 ft)
Pet safe
No — toxic to cats and dogs if ingested
Difficulty
Moderate
Propagation
Softwood stem cuttings taken in late spring or early summer root readily. Cut a 10-15 cm non-flowering shoot just below a node, remove the lower leaves, and insert into moist, well-drained compost; keep humid and shaded until rooted. Established shrubs can also be propagated by simple layering, pinning a low branch into the soil until it roots.
Fun facts
- Flower color depends on soil pH: blue in acidic soils, pink in alkaline ones, because acidity controls aluminum uptake.
- The showy "petals" are actually sepals of sterile flowers; the true fertile flowers are tiny and clustered beneath or in the center.
- The genus name Hydrangea comes from Greek words for water (hydor) and vessel (angeion), referring to the cup-shaped seed capsule.
- It contains cyanogenic glycosides, which is why all parts of the plant are poisonous if eaten.