Mountain hydrangea, tea of heaven
Hydrangea serrata · Hydrangeaceae
📷 Laitche · Public domain
⚠️ Feuilles contiennent glycosides; ingestion par chien/chat provoque nausées, vomissements et diarrhée.
The gardener's calendar
Mountain hydrangea, tea of heaven is in full bloom: enjoy it, watch watering in hot weather and let spent flowers feed pollinators before pruning.
ID card
- Common name
- Mountain Hydrangea
- Family
- Hydrangeaceae
- Foliage
- Deciduous
- Flowering
- June to September
- Adult size
- Approximately 1.5 m in height
- Hardiness
- Good, down to -15°C
- Growth
- Moderate
- Origin
- Japan
✓ Taxonomy verifiedSource: AI estimate · hardiness: reliability high.
Expert tips
The key tip
Water generously and regularly throughout the growing season: this hydrangea needs constant moisture. Keep the soil consistently moist (not waterlogged) from May through September.
The common mistake
Underestimating water needs: a hydrangea serrata that doesn't get regular watering will flower poorly and its leaves will shrivel.
The pro's trick
Slightly acidify the soil with sulfur or ericaceous compost if you want to intensify the blues.
Care
Light exposure
Mountain hydrangea prefers a partly shaded location, ideally with morning sun and afternoon shade. Avoid full south-facing exposure in warm regions, which dries out the foliage. A spot sheltered from strong winds is recommended to preserve the delicate flowers.
Watering
Keep the soil regularly moist, especially during hot periods and flowering. Water deeply 2 to 3 times per week depending on climatic conditions. Avoid complete soil dryness and stagnant water excess that would promote root rot.
Soil
Prefer rich, well-drained soil that is slightly acidic (pH 5.5 to 6.5). Amend the soil with compost or peat at planting. An organic mulch at the base helps retain moisture and regulate root temperature.
Pruning and cutting
Carry out light pruning in late winter or early spring, before growth resumes. Remove dead or damaged branches and shorten the previous year's wood by 30 to 40 cm. Remove faded flowers after flowering to encourage branching.
Fertilizer
Apply potassium-rich fertilizer in spring to support flowering. A balanced application at the start of growth is generally sufficient. Avoid excess nitrogen which favors foliage at the expense of flowers.
Diseases and pests
Mountain hydrangea can be affected by powdery mildew or leaf spots in humid conditions. Ensure good air circulation around the plant and avoid wetting the foliage. Spider mites appear in dry weather: increase ambient humidity if infestation occurs.
Did you know?
Mountain hydrangea (Hydrangea serrata) is a more delicate and compact form than the classic French hydrangea, originating from the mountainous regions of Japan. Its lacecap or platelets flowers have a fascinating property: their color varies depending on soil acidity, shifting from pink to blue according to pH. This phenomenon has captivated Japanese horticulturists for centuries and remains one of the most intriguing characteristics of the Hydrangea genus.
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
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- Fuzzy deutziaDeutzia scabra
- Oakleaf hydrangeaHydrangea quercifolia
Tips generated and checked by Viridia — adapt them to your local climate.