A small container garden at the RHS Chelsea Flower Show is highlighting the risk of flooding in UK gardens. According to new research by Flood Re, millions of homeowners in the UK could be at risk of a flooding crisis.
Research by Flood Re reveals that 82% of UK garden owners believe their gardens can handle heavy rain, yet nearly a third are unaware that paving and hard surfaces increase flood risks.
Flood Risk in Gardens
Gardens rich in plants and permeable surfaces allow rainwater to absorb into the ground, whereas those with extensive paving and hard materials generate more runoff, overburdening drainage systems.
A mere 5mm of rain in a 20-square-metre garden produces 100 litres of runoff, equivalent to a full bathtub. Combined with roof and gutter runoff across a street, heavily paved gardens significantly heighten flood risks.
Climate change is bringing increasingly unpredictable weather events, making it more important for homeowners to consider flood risk when designing their gardens. According to Flood Re, the average flood repair bill is now more than £30,000.
Managing Rainwater
“Intense rainfall alone doesn’t cause flooding – it’s all about what happens to rain when it hits the ground,” said Dr Peter Melville-Shreeve, associate professor at the University of Exeter. “Hard surfaces like our driveways and rooftops disrupt the natural hydrological cycle and stop water soaking in. “As we pave over our green spaces, a process we call ‘urban creep’, more rainwater rushes straight into our sewers. Slowing water down at source, in green spaces, gardens and around homes, can be one of the simplest and most effective ways to manage rainwater and reduce downstream flood risk.”
Managing rainwater at its source, in gardens, green spaces, and around homes, is a simple yet effective way to reduce downstream flood risks. The Flood Re: Contain the Rain garden at RHS Chelsea Flower Show demonstrates how garden design can retain and slow rainfall.
The garden’s designer, John Howlett, said, “By using planting, permeable materials and thoughtful design, you can create a space that looks great but also works much harder when it rains. It’s about turning gardens into places that don’t just shed water, but actually help manage it.”
The Flood Re: Contain the Rain garden includes innovative features like remodelled containers to store drained water. With a button press, the water is released to moisten topsoil, enhancing retention during dry periods.
Flood-Proofing Gardens
“Our garden provides a blueprint for everyday people to help flood-proof their gardens,” said Flood Re’s head of corporate affairs, Kelly Oster-Coyle, “from including a high density of trees and plants to help absorb surface water, to ensuring damp topsoil to maximise retention and avoid run off.”
The garden prominently features plants like Astilbe ‘Deutschland’ and Astilbe ‘Dark Side of the Moon’, showcasing how gardens can be both aesthetically pleasing and functional.
