Geranium Rozanne flowers for six months. Most hardy geraniums give you four to six weeks.
The explanation for that lies in the plant’s biology, and the story of how that biology was discovered starts in a Somerset retirement garden in 1989.
Table of Contents
How a Somerset Garden Produced the Most Awarded Hardy Geranium in the World
Rozanne Waterer grew 25 to 30 different hardy geranium varieties in the garden she shared with her husband Donald in the village of Kilve, Somerset. One growing season around 1989, she noticed a seedling that looked unlike the rest. The growth was stronger, the leaves were bigger, and the flowers were noticeably larger than anything else in the bed.
The man beside her was not an ordinary gardener.
Donald Waterer had spent his career as a plant breeder and secretary at Knap Hill Nursery in Surrey, a business the Waterer family had been running since the early 1700s and one of Britain’s most recognised names in rhododendron and azalea breeding. Donald bred azaleas there professionally for decades before retiring in 1976. He had also served in RAF Bomber Command during the Second World War and spent two years as a prisoner of war.
When Rozanne pointed out the seedling, his trained eye recognised it immediately. By the following season, the plant flowered continuously from June through to November.
The Waterers contacted plantsman Adrian Bloom at Blooms of Bressingham in 1991. Building sufficient stock through tissue culture took a full decade. The plant made its public debut at the RHS Chelsea Flower Show in May 2000, released under the cultivar name ‘Gerwat’, a combination of GER for Geranium and WAT for Waterer. The trademark name Rozanne was chosen to honour Mrs. Waterer. Both she and Donald had died before royalty payments reached their family.
What Makes Rozanne Geranium Different from Any Other Cranesbill
Rozanne is a natural hybrid of Geranium himalayense and Geranium wallichianum ‘Buxton’s Variety’, both native to the Himalayas. It is completely sterile, and that sterility is the direct reason behind the extended bloom period.
Because the plant cannot set seed, it continues producing flowers throughout the entire growing season, biologically attempting reproduction without ever completing it. Flowering runs from late May through to the first hard frost with no fixed endpoint. No seed-bearing geranium in the genus comes close to replicating this.
The flowers are saucer-shaped, 5cm across, violet-blue with purple veining leading into a white centre. The foliage is deeply lobed, slightly marbled in mid-green and chartreuse. As temperatures drop in autumn, the leaves shift to russet-red before the plant dies back fully for winter. At establishment, Rozanne forms a mound 45 to 60cm tall, spreading 90 to 120cm wide, covering 2 to 3 square feet in its first full season.
The formal record backs up what gardeners have known since 2000. Rozanne holds the RHS Award of Garden Merit (2006), was named the Perennial Plant Association’s Plant of the Year in North America in 2008, won the University of Georgia Georgia Gold Medal that same year, and was placed as a top pick in the Chicago Botanic Garden’s 15-year perennial trial. In 2013, a panel of leading horticultural experts chose it as the RHS Chelsea Flower Show Plant of the Centenary, the best plant introduced at Chelsea in 100 years, a decision confirmed by public vote.
How to Grow Geranium Rozanne
Rozanne tolerates clay, sandy, and most soils in between. A few details make a significant difference in how well it performs.
Planting depth: Set the crown roughly one inch below soil level rather than flush with the surface. Unlike most perennials, Rozanne establishes better slightly deeper.
Soil nutrition: Slightly low in nutrients is preferable to rich. Fertile soil pushes foliage over flowers.
Feeding: A light spring application of balanced slow-release fertiliser or compost is enough for garden beds. Container plants benefit from liquid feed once a month through the growing season, plus fish, blood and bone in spring and autumn.
Watering: Water consistently through the first season. Once established, Rozanne tolerates moderate drought in cooler conditions. Waterlogged soil causes root problems; yellow lower leaves and drooping flowers are the early warning signs.
Pruning: If the plant looks tired or sprawling around late June, cut it back by a third. It responds quickly with fresh growth and a second flush of flowers. At season’s end, cut all stems to just above soil level after the first hard frost.
Containers: A pot at least 45cm wide and 30cm deep is the practical minimum. The trailing stems drape naturally over pot edges, and the plant performs well in hanging baskets and window boxes.
Month by Month: What to Expect in the Garden (UK)
| Month | What Happens |
|---|---|
| April | New foliage emerges from the base |
| Late May | First flowers open |
| June to July | Peak bloom across the full spread of the plant |
| August | A brief pause is possible during hot, dry spells — this is normal behaviour, not a problem |
| September to October | Strong second flush; often the most vivid flowering of the year |
| November onward | Foliage turns russet before full dieback; may stay partially evergreen in mild winters |
Rozanne and Bees: What a Multi-Year Study Found
Rosybee, a UK research nursery that has run structured observational studies measuring bee visits across more than 100 garden plant species, ranked Geranium Rozanne as the top bee-attracting plant in their research, with calamint running a close second.
The open saucer shape makes the nectar accessible to short-tongued insects throughout the season. Recorded visitors across the study include:
- Solitary bees including lasioglossums and blue mason bees (Osmia caerulescens)
- Honey bees and common carder bumblebees
- Hoverflies including the marmalade hoverfly (Episyrphus balteatus)
- Meadow brown and small tortoiseshell butterflies
The same sterility that drives the long bloom period drives the pollinator visits. Because the plant never completes its reproductive cycle, nectar production continues all season, and insects return with it.
The Jolly Bee Patent Battle
In January 2000, less than a year after Rozanne’s US patent was filed, Dutch plantsman Marco van Noort introduced Geranium ‘Jolly Bee’, a near-identical plant. Blooms of Bressingham filed for patent infringement. DNA testing found no detectable difference between the two varieties. The court ordered Van Noort to cease all sales of ‘Jolly Bee’ by July 1, 2010. The RHS has since listed the two as identical cultivars.
The US plant patent, PP12,175, expired in February 2019. Rozanne can now be propagated and sold freely without licence fees. At New Zealand’s Auckland Botanic Garden, it flowers without interruption throughout the year. The Rozanne cranesbill geranium that started as an unnoticed seedling in a Somerset village holds a title no other garden perennial has claimed: RHS Plant of the Centenary, voted for by the public from a century of Chelsea introductions, and still unbeaten in the longest independent pollinator study ever run on garden plants.
