It has not been artificially watered for 22 years, yet this garden, on an exposed slope in Essex, the driest county in the UK, is bursting with bloom.
A dry bed at the Royal Horticultural Society Hyde Hall is dominated by cool greys and pale greens, and full of Mediterranean, Australian and African shrubs and flowers. Could this be the future British garden?
After the extreme temperatures of the past two weeks, a drought and the earliest autumn forecast in 20 years, is it time to rethink our plant choice and build climate-change resilience into our gardens?
In Hyde Hall, some of the magnificent clusters of the Jurassic-looking Gunnera unfortunate to be in less sheltered spots were scorched terribly when the temperature hit 37.3C a fortnight ago.
But some plants are thriving. Carpobrotus, with a daisy-type flower, is usually seen on the roadside in California, says Hyde Hall curator, Robert Brett.
A prickly pear cactus is thriving, giving the RHS motive to experiment with a full cacti and succulent bed under an overhang for shelter from winter frost next year.
Some may be horrified at losing the verdant lush and extensive colour palette in the gardens of our future, but Brett says it’s not about swapping roses for Californian poppies. Instead, gardeners should improve their approach to their use of water and paving, and start to experiment with drought-loving species. After all, RHS’s dry garden is not a desert – it has 200-300 plants.
“Plants are great at adapting to weather, but we have to adapt with that. So our approach to gardening has to perhaps change,” says Brett.
The dry garden, which was planted 22 years ago, is a just a patch of the 1,000 acre site, but has proved an important test bed for gardening in a warmer and windier climate.
Plants are watered in initially and then left to their own devices, so only the drought tolerant survive. Some, such as achilleas (yarrow), Eryngium (sea holly) and Agapanthus, are already familiar sights in British gardens, as are perennials such as lavender and rosemary, which thrive on neglect.
“It is a learning process for us all,” he says.
In addition to reviewing our choice of plants, the biggest change we need to make is our attitude to water.
Brett has been in the business for 35 years and says the biggest and most concerning changes are the wind and sudden deluges of rain, storms and flash flooding.
The RHS has teamed up with Cranfield University to help the nation switch from mains water to rain water. Its Mains2rains campaign has 10 top tips for changing our behaviour.
The greatest change we can make is not watering lawns during dry spells.
“We have this image of the classic English garden with lush herbaceous borders, nice green lawns. Our expectation has to change,” says Brett.
RHS research in its Gardening in a Changing Climate report, has shown that people are already changing their attitude to straw lawns, with a survey showing the majority of the public would rather have parched grass than a plastic alternative.
Do not use a hose. “Use a watering can instead, that way you can target your watering and you can keep those herbaceous plants you want,” says Brett.
Other recommendations include installing water butts and using drip trays beneath pots to stop loss of excess water.
Brett points to new designs of self-watering pots or baskets, which have built in reservoir spaces with wicks allowing the water to be drawn into the roots through capillary action, says Brett.
“Right plant, right place,” is a cornerstone of RHS horticulture teaching and is just as important to achieve sustainability.
Sarah Wilson-Frost, who looks after some of the dry garden at Hyde Hall, warns against placing water-loving plants alongside your dry-garden ones. She has found that Eupatorium maculatum, or Joe Pye weed, a regular of prairie gardens, actually needs quite a lot of water and meant some of the dry garden ended up needing hydration in the extreme recent heat. So it will probably be moved.
Water your plants at dusk or close to it, when temperatures are low. Watering during heat is counter-productive as the moisture goes straight up the plant and exits the leaves through the transpiration process. “It means water won’t penetrate deep into the soil, roots might start adapting and then start to become shallow”, making them less resilient in storms, says Brett.
Mulch or a cover of loose stones, bark or other material on top of bare soil helps retain moisture and will be essential in the future.
Run-off from paving, whether a domestic driveway or large expanses of land in housing and industrial developments, has long been identified as a contributor to floods.
This too is something we can change. The Rains2mains site has a section on new types of permeable paving that will “slow the flow” of rain and allow it seep into the soil beneath rather than run straight into drains.
RHS curator Robert Brett’s top five plants for a dry garden
1. Stipa ichu, a soft feathery ornamental grass that will provides spikes of creamy movement in a breeze.
2. Ballota pseudodictamnus, a small shrub that will provide mounds of pale green and small pink flowers.
3. Eschscholzia californica or the Californian poppy, a lovely yellow or orange flower which, like other poppies, will self-seed happily around your garden.
4. Hylotelephium “Purple emperor”, a magnificent sedum grown for its claret-coloured stems, purple foliage and small pale pink flowers.
5. Myrtus communis, an evergreen shrub native to southern Europe with masses of white flowers in late summer.
Walking around the garden, he also raves about these: Santolina chamaecyparissus (lavender cotton), Hesperantha coccinea (a South African native that isn’t the life of the party in the summer but is “fabulous” in the winter), the drought-tolerant and care-free Grevillea, or spider flower genus, including the exotic red bottle brush tree, but a genus of more than 300.
How to build a dry garden. Top tips from Susie Curtis, who looks after the dry garden
1. Choose a sunny, south-facing spot with free-draining soil.
2. Don’t layer the area with a membrane as this makes additional planting difficult.
3. Use smaller gravel or stones (depending on your taste) several inches deep as a mulch to allow young plants to establish.
4. Try to use a mixture of self-seeding plants and evergreen plants to give the design both structure and spontaneity.
5. The best time to plant is early autumn or spring when the soil still has some moisture and the plants can establish.
Bulbs can also be used in a dry garden and Curtis recommends Tulbaghia violacea (society garlic) as “it just keeps flowering”, Tritelieia (trumpet lilies) and Bulbine (a south African native which could be used in place of Crocosmia).
• This article was amended on 2 August 2022 to clarify details about Susie Curtis’s advice.
