Hydrangea
Hydrangea macrophylla · Hydrangeaceae
📷 belvedere04 · CC BY 4.0
⚠️ Hydrangea : feuilles et boutons contiennent des cyanogènes. Chiens/chats : troubles digestifs, faiblesse. Humains : irritation buccale, nausées par ingestion.
The gardener's calendar
Hydrangea is in full bloom: enjoy it, watch watering in hot weather and let spent flowers feed pollinators before pruning.
ID card
- Scientific name
- Hydrangea macrophylla
- Family
- Hydrangeaceae
- Type
- Deciduous shrub
- Mature height
- Up to 2 m
- Flowering
- June to September
- Foliage
- Deciduous, dark green
- Hardiness
- Down to -15 °C depending on variety
- Origin
- Japan
✓ Taxonomy verifiedSource: AI estimate · hardiness: reliability high.
Expert tips
The key tip
Hydrangea needs regular moisture (moist soil, not waterlogged) and afternoon shade in hot climates. Apply compost to the soil surface each spring without digging it in.
The common mistake
Overwatering: many gardeners drown the hydrangea and trigger fungal leaf diseases.
The pro's trick
If you want to change flower color (blue/pink), the real key isn't pH but aluminium availability: work the soil 2 years before judging.
Care
Exposure
Hydrangea prefers a partly shaded location, ideally protected from direct afternoon sun in warm climates. A spot with indirect light and 3 to 4 hours of morning sun is optimal. Avoid overly dark locations, which reduce flowering.
Watering
Hydrangea requires regular and generous watering, especially during growth and flowering periods. Keep the soil moist but not waterlogged. In summer, water deeply 2 to 3 times per week depending on temperature, and reduce watering in winter.
Soil
Rich, well-drained soil with a slightly acidic pH (5.5 to 6.5) promotes flowering. Improve the growing medium with compost or peat at planting time. Hydrangea appreciates consistent moisture without waterlogging.
Pruning and maintenance
Prune in late winter (February-March) to maintain a compact shape and encourage abundant flowering. Remove faded flowers in autumn. New shoots each year bear the flowers, making regular and gentle pruning important.
Fertilizing
Apply a balanced fertilizer rich in potassium in spring and summer to support flowering. A monthly application during the growing period is recommended. Reduce or stop nitrogen application to avoid excessive foliage at the expense of flowers.
Diseases and pests
Hydrangea can be affected by powdery mildew, mites, or aphids in warm and humid conditions. Ensure good air circulation and avoid watering the foliage. Excess humidity promotes fungal diseases; treat quickly with natural fungicides if necessary.
Did you know?
Hydrangea owes its name to the Greek words 'hydro' (water) and 'aggeion' (vessel), a reference to its significant water needs. What's fascinating is its ability to change color depending on soil pH: blue varieties remain pink in alkaline soils, while acidity enhances the blue color. This is why in Japan, hydrangea symbolizes inconstancy and adaptability.
Where to buy it
Best planted in autumn so the roots settle in before summer, or in early spring once the frost has passed. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, October, November.
Add this plant to my garden →Plants from the same family
- Mock orangePhiladelphus coronarius
- Smooth hydrangeaHydrangea arborescens
- Panicle hydrangeaHydrangea paniculata
- Mountain hydrangea, tea of heavenHydrangea serrata
- Fuzzy deutziaDeutzia scabra
- Oakleaf hydrangeaHydrangea quercifolia
Tips generated and checked by Viridia — adapt them to your local climate.