| Common Name | Diamond Rouge Hydrangea |
| Botanical Name | Hydrangea paniculata ‘Rendia’ |
| Plant Type | Deciduous shrub |
| Hardiness Zone | 3-8 |
| Mature Size | 5-6 ft tall, 4-5 ft wide |
| Sun | Full sun to part shade |
| Soil | Moist, well-drained |
| Bloom Time | Mid-summer to fall |
| Bloom Color | White aging to deep cherry red |
| Deer Resistant | Moderate |
Why Diamond Rouge for Wisconsin
Diamond Rouge produces the deepest red color of any panicle hydrangea. The flowers open white in mid-summer, then shift through pink to a rich cherry red by September. The color is darker and more saturated than Pinky Winky or Vanilla Strawberry. Compact at 5-6 feet, it fits residential landscapes without getting out of hand. Zone 3 hardy, so Wisconsin winters are no concern at all.
Planting Instructions
When: Spring or early fall.
Where: Full sun for the deepest red development. Part shade produces lighter pink tones.
How: Standard hydrangea planting. Amend clay soil with compost. Keep consistently moist for the first season.
Care Throughout the Season
Spring: Cut back to 12-18 inches in late winter/early spring. Blooms on new wood, so pruning promotes larger flower heads.
Summer: Flowers open white starting in July. Keep watered. Mulch to retain moisture.
Fall: Peak red color in September. Leave dried heads for winter interest or cut for arrangements.
Winter: Fully dormant and hardy. Dried flower heads look good with frost.
Common Problems in Wisconsin
Color disappointment: The red color needs sun and cool nights to develop fully. Plants in too much shade may stay pink rather than turning red.
Stem strength: Large flower heads can weigh stems down after rain. Hard spring pruning to a low framework produces sturdier stems.
Companion Planting
Boxwood for evergreen winter structure. Sedum ‘Autumn Joy’ for complementary fall color. Grasses for texture. Catmint at the base.
Design and Landscape Uses
Foundation plantings, mixed borders, or specimen use. The compact size works in smaller gardens. Plant where you can watch the color transformation through the season. Outstanding in a white garden that gradually turns red as summer progresses.
Fun Fact
Diamond Rouge was bred by Pepinieres Renault in France. The name refers to the diamond-shaped florets and the rouge (red) color. It holds the record for the deepest red color among panicle hydrangeas tested in controlled conditions.
Diamond Rouge is available at our Cedarburg nursery.