As a rose ensusiast and a rose blogger, I was privileged to be invited by the RHS Trials team to attend the final on-site rose evaluation session—a rare glimpse into the meticulous world of horticultural assessment that determines the prestigious Award of Garden Merit (AGM).
The RHS Rose Trial: More Than Just a Beauty Pageant
The 2021-2024 Rosa (red roses) trial was far from an ordinary garden gathering. This was the first official rose trial focused specifically on red-flowering roses, a color notoriously challenging due to its susceptibility to disease. The RHS Trials team embarked on a mission to identify the most resilient and beautiful red roses for UK gardeners.
What Makes an AGM Winner?
The Award of Garden Merit is not handed out lightly. Roses must demonstrate:
- Excellent performance in ordinary garden conditions
- Availability in the UK
- Robust constitution
- Stable form and color
- Reasonable resistance to pests and diseases
My Day at Wisley: A Rose Lover's Dream
Early morning at the RHS Wisley botanical garden was atmospheric. Entering via the employee entrance, I found myself surrounded by trial beds hosting not just roses, but also dahlias and delphiniums. The weather, typically British, transformed from cloudy to windy and rainy—a challenge that didn't deter the passionate rose experts.
The Judging Process: Precision and Passion
The evaluation was a masterclass in horticultural assessment. Detailed forms allowed judges to meticulously record observations on:
- General plant impression
- Disease resistance
- Fragrance
- Flower characteristics
- Novelty
What impressed me most was the collaborative spirit. Despite being experts, the judges shared a camaraderie that made the technical process feel almost like a celebration of roses.
The Results: A Comprehensive Review
Out of 60 different red rose selections from the UK, France, and Germany, four roses emerged victorious. As Michael Marriott, a renowned rose expert, noted, these weren't your typical cut flowers, but robust shrub roses that promise gardeners months of vibrant color with minimal maintenance.
The trial wasn't just about crowning new champions—it also served as a critical reassessment of existing AGM holders in light of changing climate conditions. Out of 60 different red rose selections, four roses emerged victorious with new AGMs, while four existing AGMs were reconfirmed or retained. However, equally significant was the decision to rescind AGMs from five previously honored varieties.
New Champions and Fallen Stars
The four new AGM winners demonstrated exceptional performance across all criteria. However, the trial also revealed how changing conditions have affected once-stellar performers.
New AGM Winners (2024)
- 'Eternity' (Noa150097)
- A tall rose (150cm) with abundant cluster flowering
- Notable for healthy foliage and bushy growth
- Hardy to H6 (very cold hardy)
- 'Lovestruck' (Dicommatac)
- Tallest of the winners (160cm)
- Scented blooms that transition from red to pink
- Hardy to H5 (cold hardy)
- Distinguished by vigor and health
- 'WB Yeats' (Dicoodles)
- Medium height (100cm) with excellent growth habit
- Features glossy foliage and abundant flowering
- Hardy to H6
- 'Cayenne' (Koroutofko)
- Second tallest (165cm) with velvety red blooms
- Heat resistant flowers with late blooming period
- Hardy to H6
- Note: Currently subject to availability
Reconfirmed Previous Winners
- 'Moment in Time' (2012) - Compact at 65cm
- 'Red Finesse' (2012) - Also compact at 65cm
Retained Previous Winners
- 'Ingrid Bergman' (1993) - Status under review
- 'My Valentine' (2012) - Medium height at 100cm
This collection represents a range of heights from compact (65cm) to tall (165cm), with most varieties showing excellent hardiness (H6 rating). The new winners particularly excel in disease resistance and vigor, crucial traits for modern gardens.
Five roses that had their AGMs rescinded (lost AGM award status):
- ROYAL WILLIAM ('Korzaun') - Once celebrated, this rose showed diminished vigor and increased susceptibility to new disease strains
- THINKING OF YOU ('Frydandy') - Struggled with survival, with only one small plant remaining by year three
- THE TIMES ROSE ('Korpeahn') - Failed to meet current plant health and vigor standards
- TRUMPETER ('Mactru') - Despite its bright blooms, lost its historical vigor and disease resistance
- DARCEY BUSSELL ('Ausdecorum') - No longer met health criteria and has been 'retired' by David Austin
Expert Assessment
The evaluation process brought together twelve distinguished judges, representing a broad spectrum of horticultural expertise. The panel included:
- Leading rose experts like Michael Marriott and Charles Quest-Ritson
- Industry professionals from the British Association of Rose Breeders
- Collection holders and garden writers
- Specialists from the Royal Parks and RHS
Meeting four times annually from June to September between 2022 and 2024, this diverse group ensured a thorough and balanced assessment of each variety.
The AGM red rose trials judges were:
- Kerry Austen (Chair, Rochfords International Rose Trials),
- Ian Kennedy (British Association of Rose Breeders),
- Emily Lamey (Horticulturist),
- Louisa Mansfield (Future Gardeners),
- Michael Marriott (Rose expert and rose garden designer),
- Daniel Myhill (National Collection holder, Head of Breeding at David Austin Roses),
- Charles Quest-Ritson (Author of RHS Encyclopedia of Roses),
- Mark Rowe (Horticulturist),
- Janice Shipp (Garden writer),
- Marilyn Stevens (Roses UK),
- Adam Stoter (Royal Parks) and
- Rod White (RHS Woody Expert Group).
Beyond the Blooms: What This Means for Gardeners
This trial represents more than just a list of award-winning roses—it's a crucial update for UK gardeners in an era of climate change. The rescinding of previously awarded AGMs demonstrates the RHS's commitment to maintaining the highest standards and acknowledging how changing conditions affect plant performance. For gardeners, this means they can trust that AGM-holders are truly equipped to handle contemporary growing challenges.
A Triumph of Resilience
The trial wasn't just about beauty. Challenges like rust, black spot, and even stem-boring sawflies tested each rose's mettle. The winners proved they could withstand the unpredictable British climate and still look stunning.
Beyond the Blooms: What This Means for Gardeners
This trial represents more than a list of award-winning roses. It's a testament to the RHS's commitment to helping gardeners make informed choices. The AGM is a seal of approval that speaks to a plant's reliability, performance, and garden-worthiness.
Final Thoughts
My day at the RHS rose trial was a reminder of the intricate science and pure passion behind every bloom in our gardens. For gardening enthusiasts and professionals alike, these trials are a beacon of horticultural excellence.
Full trial results for the red rose trial are available on the RHS website. The next rose trial at the RHS Wisley Garden will be for the Rosa Persica variety, which I also plan to visit and report on here. Watch this space for more rose trial information. Happy gardening!
Link to the RHS plant trials in case you want to learn more about trials for other plants.
If you want to know more about the rose trials, their history, and varieties, check my blog about the rose trials.
And a few more rose photos from my visit to the RSH trial garden on the last day of the AGM Red Rose trial. Enjoy.
