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It has been a rainy first half of 2024, by anybody’s standards. We’re halfway through July, and already this month England has seen 97 per cent of its average July rainfall. It’s been a tricky growing season, with many gardens becoming waterlogged, or even flooded. Our seedlings were first swamped, then decimated as the slugs and snails went into overdrive.
It got us to thinking about the techniques for managing water we saw at this year’s RHS Chelsea Flower Show – in particular in the Flood Re: the Flood Resilient Garden.
The Flood Resilient Garden
We visited this garden quite a lot during the show, as we’d provided some kit for its construction. It was co-designed by Naomi Slade and Dr. Ed Barsley, pictured here with Monty Don (left).
'Rain' fell on the garden regularly throughout the day, showing how the garden had been designed to cope with sudden deluges. On sunny days this produced a glorious rainbow which was one of our favourite things about the show.
But it was on the rainy days that this garden came into its own. And we certainly did have rain during the show this year. If you were there on the Tuesday or Wednesday this year, you’ll have witnessed the phenomenon of the Chelsea Monsoon. Trade stands subsided, greenhouses were bailed out, moats formed around marquees.
But the Flood Resilient Garden calmly carried on doing what it did best: dealing with the downpours and continuing to look exquisite.
The highs and lows in garden design
Set in a 9m x 6m domestic family garden, the garden was constructed around a sunken pond area, with raised areas at both ends of the plot. The slopes were packed with dense planting, designed to help slow the flow of rainfall. The rain filters down through layers of greenery as it falls. This means it doesn't all reach the soil at once as a deluge, and so it will run off more slowly.
At either end of the garden, a deck and an elevated mound gave plenty of places to sit and enjoy the garden, following the sun during the day. The two raised areas were linked by stepping stones across the sunken pond, or there was also a route via a delightful bridge over a swale.
What is a swale? Many of us domestic gardeners in the UK hadn’t come across these until relatively recently. A swale is simply a shallow channel used to collect or move water. It can store water allowing it to seep away gradually, and it can be planted, to slow the flow and act as a filter.
In the Flood Resilient Garden, during heavy rainfall the swale became a stream, channelling water into the pond to seep away naturally.
Create planting zones with drainage
We thought the vibrant colours in the garden were a joy, with lush green planting and pops of rich jewel-bright colour. The range of planting was very wide, thanks to the drainage created by the sloped ground around the pond. Plants which prefer well-drained ground were simply lifted up out of the damper ground.
Roses, poppies, peonies, erigeron, all those much-loved garden favourites featured, happy on their sunny banks. They nestled cheek-by-jowl with plants in the lower levels, which were happy with their feet wet. We loved the striking contrasts this created - sun-loving poppies next to the gorgeous vibrant stems of the moisture-loving willow.
The planting also included edibles, planted on the higher levels away from flood risk from potentially contaminated water. A quince tree, needing really well-drained soil, was raised on the mound, demonstrating that all types of plants could be included.
Stylish water storage
At the deck end of the garden, large galvanized re-purposed water tanks doubled as cascading ornamental ponds. We learned that these had the capacity to hold ten bathtubs of water – that’s enough to cope with a truly exceptional, once-in-a-hundred-years storm. This was a surprise, as they looked so unobtrusive, stylish even, beautifully planted with a range of bog plants.
The tanks store water for later use, crucial in our increasingly unpredictable climate. Water from the pergola over the deck was collected and channelled into the tanks via rain chains. The guttering downpipes were disconnected, all run-off going into the tanks as usable water.
There was also a ‘smart’ water butt, programmed to empty ahead of heavy rain. This pre-waters the soil, helping it to absorb rainfall since dry soil is less able to take up water. The butt then fills up again during the storm.
Flooding: be part of the solution
One in eight gardens in the UK has flooded in the last year, and one in four properties is at risk. We really need to start thinking about how we manage water in our own plot. We can all be part of the solution.
In the Flood Resilient Garden, the pond can hold 100 bathtubs of water, an astonishing volume. It’s large enough to reduce flooding not only in this garden, but also in ten surrounding properties.
And should the worst come to the worst, the garden’s flood barrier protected the home’s doorways, highlighting how for many people, flooding is now a very real risk. Can we all say that we have considered how to protect our homes and gardens as flooding increasingly becomes part of our lives?
Here's what we learned from the garden:
1) Think in three dimensions – raise areas to keep them drier, lower areas to give water somewhere to go. In a smaller space, use a raised bed.
2) Right plant, right place – if the drainage is right, you can have drought-tolerant plants and moisture-loving plants in the same garden.
3) Disconnect your downpipes – hold on to and celebrate the water in your garden. It’s a super-important resource for periods of drought, but also run-off causes problems, in terms of flooding, overburdening of drainage, sewage release, etc.
4) Make a feature of water management – pretty water storage ideas, rain chains, planted boggy areas can all easily be incorporated.
5) Every little helps - as gardeners we have the power to help mitigate the impact of a changing climate, by adapting our outdoor spaces to better cope with heavy rainfall and periods of drought.
