How to plant a low-carbon garden
11th November 2021
A garden designed to absorb carbon is a plant-lover’s heaven. The more plants you grow, the more carbon dioxide your garden can lock away – so it’s the best excuse to pack in as many plants as you can.
Plants take in carbon dioxide during photosynthesis, much like we breathe oxygen. They then convert it into glucose, which helps them to grow.
So when you put plants front and centre, keeping hard landscaping to a minimum, your garden becomes a living sponge, sucking carbon dioxide directly out of the air.
Here are five ways to make the most of your garden planting’s carbon-capturing potential.
1. Plant in layers
Think in canopies, like those of a forest. Layered planting puts taller trees overhead, underplanting them with shrubs, then perennials and ground cover, all densely planted to knit together and create a seamless tapestry of greenery.
Plant a wide mix of trees, shrubs, perennials and ground cover, and your garden will become a miniature carbon sink. Trees are so efficient at extracting carbon dioxide from the atmosphere that planting them has become a recognised way of “offsetting” your carbon emissions in other areas of life. So why not offset at home?
2. Plant permanently
Peonies are classic long-lived herbaceous perennials, each clump can live for many decades
Tender bedding plants are raised in heated spaces and replanted yearly, so have a high carbon cost
The more you plant and replant, the more you have to cultivate the soil, disturbing fragile ecosystems and releasing the locked-in carbon underground. Focus on displays of long-lived, low-maintenance perennial plants that stay in place for many years.
3. Love your shrubs
Plants with a woody, permanent framework of branches lock up most carbon, but your choice isn’t limited to trees. Shrubberies and hedgerows are really effective carbon sinks, and shrubs can often work well in gardens that are too small for trees.
Fast-growing plants and those with extensive root systems are particularly effective at capturing and holding on to atmospheric carbon. Bamboo in particular is a superstar in this regard, but pick a less-invasive clump former such as Chusquea, Fargesia or Dendrocalamus.
Put plants front and centre and your garden becomes a sponge, sucking carbon dioxide directly out of the air
4. Work with your garden
Many plants love dry conditions, it’s just a case of picking the right ones. Remember, watering your garden has a carbon cost too
In damp gardens, save cash and carbon by growing plants that enjoy the conditions, such as Siberian iris, instead of installing drainage
Plants thrive when grown in the right conditions and will need fewer carbon-hungry inputs like fertiliser. Plant sun-lovers in the driest spots and site your pond where rain collects naturally in winter. Try to choose plants that won’t outgrow the space, so you don’t have to keep cutting them back.
Use the RHS Find a plant tool to help you pick the right plant; explore the filters to discover plants that will thrive in your conditions and fit the space available.
5. Design close to home
Native and non-native plants absorb carbon equally well. But some demanding, non-native plants that grow slowly and require high levels of fertilizer, watering, and extra heat may end up costing more in carbon emissions than they absorb – especially if they’re imported too. So pick natives and hardy non-natives wherever you can.