Hydrangea care — light, water, toxicity and hardiness
Hydrangea (Hydrangea macrophylla) wants partial shade and a drink about every 3 days once established. It is hardy in USDA zones 6 to 9. It is toxic to pets — worth keeping out of reach.
| scientific name | Hydrangea macrophylla |
|---|---|
| family | Hydrangeaceae |
| category | flower |
| plant type | perennial |
| light | partial shade |
| water cadence days | 3 |
| min zone | 6 |
| max zone | 9 |
| frost tolerant | true |
| toxic to pets | true |
| toxic to humans | true |
| edible | false |
How often should I water Hydrangea?
Hydrangeas are thirsty — water deeply and mulch well.
Is Hydrangea toxic?
Leaves and flower buds contain cyanogenic glycosides — toxic to pets and people if eaten.
Who eats it
Palatable to browsing animals such as deer: low. Palatable to people: no.
What it needs
Its shade tolerance is low. Its moisture use is low. Its drought tolerance is medium. It wants at least about 35 inches of rain a year. Above roughly 55 inches of annual rain it struggles. It tolerates soil down to pH 4.5. It tolerates soil up to pH 8.0. Its fertility requirement is medium. Adapted to coarse, sandy soils: yes. Adapted to medium, loamy soils: yes. Adapted to fine, clay soils: yes. It needs at least 145 frost-free days. Fire resistant: no. It has been recorded down to -13°F. It suppresses neighbours chemically: no.
How it grows
It grows as a multiple stem form. Its growth rate is rapid. Its lifespan is moderate. It puts on most of its growth in spring and summer. It resprouts after damage: yes. Coppices: no. Its tolerance of hedging is medium. At maturity it reaches about 4.0 feet. By twenty years it is about 4 feet. Its roots go down at least 12 inches. Its shape is semi-erect. It holds its leaves through winter: no.
What it looks like
It blooms in indeterminate. The flowers are blue. Conspicuous in flower: yes. The foliage is green. The foliage texture is coarse. In summer the canopy is moderate in porosity. In winter it is porous in porosity. Fall colour: no. Fruit begins in summer. Fruit finishes by fall. The fruit persists on the plant: no. The fruit is conspicuous: no.
Growing more of it
Propagated by seed: no. Propagated by cuttings: yes. Propagated by container: yes. Propagated by bare root: yes. Propagated by bulb: no. Propagated by corm: no. Propagated by tubers: no. Cold stratification required: yes. Commercial availability: routinely available.
Source: USDA PLANTS Database; US Cooperative Extension horticulture publications · ASPCA Toxic and Non-Toxic Plant List · 2026-09-02