I didn’t get to the Chelsea flower show this year, or any year come to think of it, but I was curious to see what the Royal Horticultural Society was up to with their urban garden. The RHS has done some great work on gardening in a changing climate, assessing the changes as they happen and are likely to happen, and advising gardeners on how to maintain a thriving garden. This year, they launched a new report, Gardening Matters: Urban Gardens, that suggests ways to fight climate change in your own garden. (It isn’t available online yet, I will link in when it is)
According to their study, gardens play several important roles. In an urban environment, gardens help to control both extreme heat and extreme cold. They can absorb excess rainwater and protect against flooding – especially important in front gardens, as I’ve written about before. Gardens encourage human welfare and animal welfare, providing habitats for birds, insects, frogs and small mammals.
Water is one key aspect of gardening in a changing climate. At the time of writing, we’ve just had the for a century in this part of the UK, with less than half the average rainfall. If that sort of water shortage becomes more common, we’re going to have to find ways to use water more wisely, and harvest more rainwater when it is available. The RHS has pioneered both, reducing its water use by 40% at its demonstration gardens at Wisley. (If you don’t harvest rainwater already, your local council can offer you a water butt at a subsidised price.)
Drought resistant plants are another line of investigation, and RHS runs an experimental ‘‘ at Hyde Hall in Essex. That includes plants and varieties from the Mediterranean or California. Silver-leaved plants reflect sunlight and can help cool a garden. Succulent plants retain water, and ground cover can help retain water and prevent evaporation. Some gardeners spend their lives trying to eradicate clover from their lawns, but clover is a great ground cover plant for growing between larger plants, and it will fix nitrogen while it’s at it. Mulching with straw or bark chips can also create a water-retaining layer across the soil, ensuring that more water stays in the ground for plants to use.
If you’re one of the many English gardeners who value a nice lawn, allowing a little diversity into the mix will actually keep it greener for more of the year, where a pure grass lawn will dry up and go brown in peak summer unless you water it intensively. A little moss retains moisture, and clover stays green in dry conditions, so remove the bigger weeds by hand rather than blitzing them with chemicals and keeping a lawn monoculture. Clover is also good for bees, so there’s a double pay-off, if you can live with the risk of stepping on one barefoot.
You can also grow plants that will improve the energy efficiency of your home. In his fascinating book Plants for a Future, Ken Fern describes how ivy growing across a wall can insulate your house in winter and keep it cool in summer. In winter, it reduces wind chill and keeps an insulating layer of air between the wall and the air. In summer, ivy blocks solar heating and lowers indoor temperatures.
Another way to mitigate against rising temperatures is to plant more trees. Trees capture pollution and absorb CO2, and offer shade. They also provide windbreaks and reduce dust. If you want to plant more trees on your land, there is a that suggests which ones are most likely to survive drier conditions. Given the growing time involved, it makes sense to start planting more drought resistant varieties sooner rather than later.
The other side to drought is flooding. In a destabilised climate, rainfall tends to arrive all at once, and flooding is an increased risk. It is possible to design parks and gardens to help with flooding. In a garden, sinks and run-offs allow water to be absorbed by the ground, rather than run into sewers or drainage systems. In a park, streams can be bounded with natural banks and floodplains, so that overspill can be managed and even turned into an advantage.
Finally, growing more of our own food is a way of reducing food miles and reducing our carbon footprints. Few of us could ever be self-sufficient, but the more we can grow for ourselves, the more energy we can cut from the food supply chain. We can also grow more perrenials, which continue to yield crops year after year, saving energy in turning soil and replanting.
I’ve been trying out a few of these things in our own garden. I have rainwater harvesting barrels front and back, and I intend to fit a large water tank when I find one of the right size and shape. I’m growing more mediterranean vegetables this year, including a variety of different squashes and beans. I’m also using climbing sun-loving plants as cover for less hardy, shade-loving plants grown beneath them. A neighbour from New Zealand has given me some seed for a drought-resistant Kiwi spinach, which I have yet to plant.
Anybody else trying anything different?
- For more on gardening in a changing climate, see Debbie’s .