In a striking horticultural anomaly, exotic Tree Dahlias are flowering days before Christmas along Britain's Jurassic Coast, thanks to an unusually mild start to the winter.
A Floral Surprise in December
The absence of significant frost has allowed the Dahlia imperialis, a plant native to Central America, to flourish at Abbotsbury Subtropical Gardens in Dorset. Typically, this plant struggles with the UK climate, but temperatures reaching a balmy 15°C (59°F) in the first half of December have created ideal conditions.
Dave Pearce, curator at the gardens, confirmed the unusual event. "Tree dahlia can grow 8ft tall and usually flowers in December," he said. "This means that the flowers get frosted, and rarely flower in the UK. Ours are flowering due to the mild winter and should be flowering on Christmas Day."
The Remarkable Tree Dahlia
The Dahlia imperialis is an impressive specimen. Key characteristics include:
- It can grow up to 8 feet tall, with some specimens reaching nearly 4 metres (12 feet) in a single summer.
- It features long, thick, bamboo-like stems and large, elder-like green leaves.
- Its blooms are a soft pink-purple with distinctive orange centres.
- It is native to a range of countries from Mexico through to Ecuador, typically found in subtropical mountain foothills.
In the UK, it is often treated as a foliage plant because blooms usually arrive too late to survive the frosts. Nurseries typically recommend growing it in a greenhouse to have any chance of seeing it flower.
A Broader Climate Trend
This early bloom is not an isolated incident but fits a wider pattern. The Met Office recently announced that 2025 is likely to be the hottest year on record, as climate change continues to push global temperatures higher.
The phenomenon at Abbotsbury follows another unusual event earlier this year when the Puya Alpestris, a plant native to the Chilean Andes, flowered at the gardens in July for the first time in five years. The Dorset site is home to over 6,000 species of plants from across the globe, making it a unique barometer for changing climatic conditions.
For gardeners, the Tree Dahlia's performance this year offers both a spectacular display and a potent reminder of the shifting environment. Its ability to prosper in a frost-free situation highlights the tangible effects of increasingly mild British winters.
