Geranium 'Rozanne'
Geranium ‘Rozanne’ is a hardy cranesbill known for its very long bloom and reliable garden performance. Plants form spreading mounds that weave among neighbors without becoming invasive. Violet‑blue saucer‑shaped flowers with a white eye appear from late spring into fall in many climates. Flowering can pause in extreme heat, then resume as temperatures moderate. It grows well in full sun to part shade in well‑drained soil. Plants are winter‑hardy through much of the northern and central United States.
At‑a‑glance
- Group/Class: Hardy geranium hybrid
- Height × spread: 12 to 18 in × 12 to 24 in (30 to 45 cm × 30 to 60 cm)
- Bloom window: Late spring to fall; main flush early summer
- Color & flower form: Violet‑blue, saucer‑shaped flowers with white eye and purple veins
- Fragrance: 0 none
- USDA hardiness: Zones 5 to 8
- Breeder / Year / Origin: Gomer and Rozanne Waterer, 2001, UK
- Awards/registration: RHS Plant of the Centenary 2013; RHS AGM; U.S. Plant Patent PP12,175; Missouri Botanical Garden Plant of Merit
- Pet safety: unknown
How it differs
- A true hardy Geranium, not a frost‑tender Pelargonium.
• Very long bloom relative to many hardy geraniums.
• Spreading clump rather than a stiff upright mound.
• Handles summer heat better than many hardy species when soil drains.
Strengths
- Extended bloom documented by botanic garden trials.
• Good heat tolerance for a hardy geranium.
• Supports pollinators.
• Low maintenance in well‑drained soil.
Care in one minute
- Plant in full sun to part shade in well‑drained, moderately fertile soil.
• Water during dry spells; avoid waterlogged sites.
• Feed lightly in spring.
• Shear after first flush if growth flags in midsummer to prompt rebloom.
• Hardy in much of the region; no special winter cover needed in zones 5 to 8.
• Divide clumps to manage spread if required.
Watch‑outs
- Flowering may slow in peak summer heat; shear lightly to refresh.
• Needs space to spread.
• Some susceptibility to leaf spots and rusts if crowded or overwatered.
Best uses (tags)
borders; groundcover; pollinators; containers; long‑season
Provenance note
A selected hybrid between Geranium wallichianum ‘Buxton’s Variety’ and G. himalayense from Somerset, England; protected by U.S. Plant Patent 12,175 in 2001.
References
- Missouri Botanical Garden – Geranium ‘Gerwat’ ROZANNE
- Royal Horticultural Society – Geranium Rozanne (‘Gerwat’) and award
- U.S. Plant Patent PP12,175 – ‘Rozanne’ (via USPTO/Google Patents text)
- Penn State Flower Trials – Geranium ‘Rozanne’ performance notes
Written by: Your Flowers Guide editorial team
We are a small independent group of flower lovers who research and review each guide using trusted horticultural and educational sources. Learn more about us