Cold-hardy beauty with elegant lacecap blooms.
Mountain hydrangeas are compact, resilient shrubs ideal for borders, containers, and smaller gardens.
Native to the mountainous regions of Japan and Korea, they offer better cold tolerance and improved blooming in cooler climates compared to their bigleaf cousins.
Overview
| Botanical Name | Hydrangea serrata |
|---|---|
| Common Names | Mountain hydrangea, Tea of Heaven |
| Zones | 5–9 |
| Exposure | Full sun to partial shade |
| Height/Spread | 2 to 5 ft tall, 2 to 6 ft wide |
| Growth Habit | Bushy, mounding, compact |
| Bloom Time | Early summer to fall |
| Flowers | Lacecap blooms in blue, pink, or lavender (color depends on soil pH) |
| Foliage | Dark green, serrated leaves with some red or burgundy fall color in certain varieties |
Why Choose Mountain Hydrangea?
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Thrives in colder climates where bigleaf hydrangeas struggle
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Reliable blooming due to cold-tolerant flower buds
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Compact size makes it perfect for containers and smaller spaces
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Pollinator-friendly and long-lasting summer color
Planting Tips
When to plant:
Plant in early spring or fall to avoid temperature extremes.
Where to plant:
Choose full sun to partial shade. In northern zones, full sun is fine. In warmer climates, afternoon shade helps prevent leaf scorch.
How to plant:
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Prepare the soil by loosening and enriching with compost.
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Dig a hole twice as wide and slightly deeper than the root ball.
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Place the plant so the root ball is level with the soil surface.
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Backfill, water thoroughly, and apply mulch.
In containers:
Use high-quality potting mix, ensure good drainage, and leave a couple inches at the top for watering.
Ongoing Care
Soil:
Rich, well-drained soil. Mulch helps conserve moisture and regulate soil temperature.
Watering:
Keep the soil evenly moist, especially in summer. Avoid letting it dry out completely.
Fertilizer:
Feed in early spring with a balanced slow-release fertilizer. To change bloom color:
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For blue flowers: add sulfur or aluminum sulfate
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For pink/red flowers: add lime
Pruning:
Minimal pruning needed. Older varieties bloom on old wood—prune after flowering. Newer varieties bloom on both old and new wood and can be lightly shaped in spring.
Pests and diseases:
Generally disease-resistant. Watch for aphids, slugs, and Japanese beetles. Avoid overwatering to prevent root rot.
Frequently Asked Questions
Do mountain hydrangeas like sun or shade?
They prefer morning sun with afternoon shade, especially in hot climates.
Do they bloom all summer?
Yes—especially reblooming varieties, which flower from early summer through fall.
Should I deadhead them?
Not required, but removing spent blooms can keep the plant looking tidy.
Do they bloom on old or new wood?
Older varieties bloom on old wood; reblooming types bloom on both.
Are they deer resistant?
No. Deer may eat the flowers and new growth. Use deterrents if needed.
Are they toxic?
Yes—mildly to moderately toxic to pets and children if ingested.
Featured Variety: Let’s Dance Sky View®
Botanical Name: Hydrangea macrophylla x serrata
Zones: 4–9
Size: 2 to 3 feet tall and 2 to 4 feet wide
Color: Blue, pink, or purple (depending on pH)
This reblooming hydrangea combines the best traits of mountain and bigleaf types. It flowers on both old and new wood, providing a long and reliable bloom season—even after late spring frosts. To enhance blue tones, amend soil with aluminum sulfate.
Landscaping Ideas
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Use in borders, foundation plantings, or massed along a slope for erosion control
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Place in containers for patios, entryways, or balconies
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Combine with peonies, roses, foxglove, and lavender for a cottage garden effect
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Plant along paths or fences to define spaces or create privacy
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Attract pollinators in mixed beds with perennials and other flowering shrubs
