Bigleaf hydrangea care guide
Hydrangea macrophylla
Also known as: French hydrangea, Hydrangea
Pets and children
Considered toxic
Leaves, buds and flowers hold cyanogenic compounds; dogs, cats and people have been poisoned, mostly with vomiting and diarrhea, so keep it out of reach and consult a veterinarian (or a doctor, for a child) if eaten.
How often to water Bigleaf hydrangea
- Spring–Summer (Mar–Sep)
- Every 2 days
- Thirsty: water until it drains from the base once the topsoil dries, as a guide; in midsummer that can mean morning and evening.
- Autumn (Oct–Nov)
- Every 3 days
- As it cools the soil dries more slowly, so water about when the topsoil has dried.
- Winter (Dec–Feb)
- Every 7 days
- Leafless in winter, water a few days after the soil dries, as a guide; letting it dry out weakens the spring buds.
Light and placement for Bigleaf hydrangea
Morning sun and light afternoon shade suit it, as a guide; full midsummer sun scorches the leaves and dries the pot, while deep shade means fewer flowers.
Overwintering Bigleaf hydrangea
Overwintering guide: −10°C (14°F) or above
Hardy and generally overwinters outdoors leafless; the flower buds sit at the branch tips, so no winter cutting back, and pots go under the eaves out of cold wind.
Fertilizing and repotting Bigleaf hydrangea
Fertilizer
Organic slow-release feed in January or February and a light feed after bloom in July are usually enough; for blue flowers use a fertilizer made for blue hydrangeas.
When to repot
Autumn (Oct–Nov), Winter (Dec–Feb)
Common problems with Bigleaf hydrangea
- Cut back after August or in early spring, it loses the flower buds and does not bloom.
- Drying out in midsummer wilts the leaves and spoils the flowers.
- A gift pot kept in a dim room for weeks weakens.
Tips for growing Bigleaf hydrangea
- Prune right after flowering, by the end of July, about two nodes below the bloom.
- Flower color follows soil acidity in many varieties: acidic leans blue, alkaline leans pink.
- Cuttings of young shoots in June or July root easily.
These are AI-generated general guidelines. They vary with the variety, the placement and the pot size. For effects on pets or children, consult a veterinarian or a doctor.
Keep your plant log going
Greenery is a free app that keeps your plant care going, with watering reminders and photo records. Available on iOS and Android.
