RHS Hampton Court Palace Garden Festival

Threatened Plant of the Year at RHS Hampton Court 2025

Plant Heritage, the plant conservation charity, hold their annual search for rare and unusual cultivars which are no longer available commercially. The finalists are displayed at the show where you can cast your vote for Public Choice in the Floral Marquee

Winner of the RHS Threatened Plant of the Year 2025

Delphinium ‘Alice Artindale’

Delphinium 'Alice Artindale'

Delphinium ‘Alice Artindale’ is a rare double rose-bud type with unique sepal layers, seldom seen today. First registered by William Artindale in 1936, it won Awards of Merit for both exhibition and garden use. The entrant, Graham Austin of Home Farm Plants in Hertfordshire, has grown it for over 15 years after being asked to identify it at a plant fair. Though slow to propagate and prone to setbacks, it thrives when left undisturbed, producing tall stems of striking blue flowers with a pink tint that are great for cutting.

Winner of the People’s Choice 2025

Tetrapanax papyrifer ‘Di Sue Shan’

Tetrapanax papyrifer ‘Di Sue Shan’ was voted as the winner in the People’s Choice award by visitors to the Plant Heritage stand throughout show week. A lesser-known cultivar, and often overshadowed by the well-known ‘Rex’ (an exotic architectural woody shrub, known as the ‘rice paper plant’), ‘Di Sue Shan’ is much bigger, more upright, faster growing and matures quicker, implying improved hardiness. It was collected at Dasyueshan, Taiwan, and named after Diane Doughty and nursery partner Sue Wynn-Jones. It is now grown at English Heritage’s Walmer Castle in Kent.

Tetrapanax papyrifer ‘Di Sue Shan’

© English Heritage

About the competition

Established by the horticultural conservation charity Plant Heritage in 2020, the annual Threatened Plant of the Year competition shines a spotlight on beautiful plants from gardens past that are in danger of being forgotten. From changing fashions to nursery hardships, many cultivars risk being lost to the annals of time, and not because of a lack of beauty, quality or garden worthiness.

This competition draws attention to some wonderful once-popular or rarer gems – in the hope that they might be propagated and planted once more. You don’t have to be a specialist to enter: any garden enthusiast or flower fanatic is invited to submit a nomination. To be eligible, the plant must simply be a named cultivar that was grown and sold in the UK or Ireland prior to 2015, but is no longer commercially available.

To find out more, visit the Plant Heritage website.

Shortlisted for 2025

You might also like...

Get involved

The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.