Talk about climate change appears endless. Most would agree that our summers feel warmer, sometimes too warm. And you will hear a lot said about carbon dioxide in the atmosphere and its role in warming our planet.
Here is a little physics. Everybody knows that when you walk into a greenhouse, the inside is warmer than the outside. That’s caused by what is known as the “greenhouse effect”. What happens is that once the light has passed through the greenhouse glass and bounces around inside, its wavelength gets longer, and you feel that change as heat. This longer “infrared” wavelength radiation cannot easily escape, and the greenhouse gets hot very quickly.
Similar things happen in the atmosphere where carbon dioxide is associated with infrared radiation and contributes to warming as in our greenhouse. And the more there is of it, the warmer it gets. Whatever is going on in the clouds, it matters to us gardeners because we have our gardens to look after.
Never mind all the physics, what does all that mean for gardeners? Many now have more water butts than ever; we have fourteen, all made from dustbins and storage boxes. Assuming none of us wants to give up our gardens and also assuming that there is a limit to how much water we can use, then having plants that can survive only on what falls as rain might be a good thing. Or if you prefer: they don’t need any extra water.
Believe it or not, there are plants that only need the water that the weather brings, and there is no need to give them any more. We first came across this group of plants in the garden of the late Beth Chatto in Essex where, 30 years ago, she established what came to be known as the “gravel garden”. And in that time, none of the plants have been artificially watered. It is still open to the public and not that far away. We have been there many times, and some of the plants in our garden came from this experimental project.
Beth Chatto wrote a book about it called “The Gravel Garden,” which is still in print. So here are some of the plants which we have grown, all of which started off in her garden.
- Melianthus major. This is one of the finest architectural plants you can grow. It is not fully hardy in the UK, but in Beth Chatto’s garden, they successfully mulch it every autumn.
- Ballota pseudodictamnus. Usually evergreen and fine in an exposed position in full sun. Very attractive grey perennial.
- Helianthemum. The rockrose. Almost evergreen ground-covering alpine. There are several varieties to choose from and in a wide range of colours.
- Thymus lanuginosus. Woolly thyme. This is a very low-growing thyme covered in strong purple flowers in the spring. Fabulous if you have some gravel to cover up.
- Bergenia cordifolia. Elephant’s Ears. It’s called elephants’ ears because that’s what the leaves look like. Evergreen with usually large pink or white flowers in the spring.
- Euphorbia myrsinites. A very useful low-growing Euphorbia that can be treated as an alpine.
- Sedum spathulifolium. There are loads of these hardy alpine Sedums to choose from and all are worth growing.
- Stipa gigantea. This is the giant oat grass, and it really does get six feet tall. Great at the back of a border.
- Lychnis coronaria. A classic cottage garden plant, grey leaves with a very unlikely carmine flower, and it will self-sow and run true.
- Kniphofia triangularis. These come from the drier parts of South Africa. Flowers orange in late summer and shouldn’t get much taller than three feet.
We gardeners are always ready to take on new ideas if they’re good for our gardens, and we’re always ready to learn from others. Please have a look at what Beth Chatto has done in her garden.