But trees are far from the only plants that can help offset your garden’s carbon footprint. Native grasses have extensive root systems — reaching more than 2 feet into the ground — and act as a storehouse for carbon, which seeps into the soil as the roots die and decompose.
Woody shrubs like spindle and bramble and herbs like rosemary and thyme can help increase your garden’s carbon stocks, recommends Nex in her book.
If you want to spice up your garden with colorful plants, it’s best to avoid annual flowers, which have to be dug up each year and release trapped carbon in the process, and instead opt for hardy perennials like peonies and sunflowers, Nex says.
Planting hedges is another worthy investment. A well-grown hedge rich in biomass helps siphon carbon from the atmosphere into plants and soil. One study found that hedgerows store similar amounts of carbon as forests. Hedgerows are also home to rich biodiversity and teeming with wildlife. A British ecologist monitoring an old hedgerow near his home in Devon counted a remarkable 2,070 species, from pollinators to lizards and mammals, visiting or living there.
Ponds can also play an important role in gardens’ fight against climate change. A study of small lowland ponds in north-east England found that they store much more carbon (79-247g per square meter per year) than the surrounding forest or meadow (2-5g).
However, not all ponds act as carbon sinks. A US study found that artificial ponds used to collect rainwater in Florida emit more carbon than they store in their muddy sediment.
“This finding means that some ponds are doing us a disservice to the ecosystem,” said Mary Lusk, study co-author and assistant professor of water and soil sciences at the University of Florida, when the study was published. “Our results suggest that when they are new, [the ponds] emit large amounts of carbon from the landscape.”
Ponds can also emit large amounts of strong methane into the atmosphere. A study by the University of Exeter concluded that ponds smaller than one square meter are responsible for the release of around 40% of all freshwater methane emissions.
However, not all environmental benefits are related to carbon – and ponds offer many other benefits such as: B. the promotion of biodiversity. In fact, some charities say adding a pond to your backyard is one of the best things you can do for wildlife (more on that later in the series).
“When you stir up the mud at the bottom of the pond, your pond releases more methane than it absorbs carbon,” says Nex. To curb the noxious gas, Nex recommends removing dead leaves from your pond surface, as rotting debris gives off methane and crosslinks it in the fall.
Gardeners who adopt low-carbon practices will be rewarded with thriving biodiversity and borders full of lush plants.
“My plants are growing much better now. It’s very flattering for me as I don’t do much!” says Nex. “It has really improved the look of my garden – it’s actually quite stunning.”
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