How to create a pollution-absorbing garden | House & Garden

A farm turned garden near Toledo in Spain by landscape designer Fernando Martos

Trees have long been heralded the lungs of the planet, but increasingly plants are being deployed not just to absorb carbon dioxide, but to metabolise and reduce all manner of nasties from our ever-more polluted air. Plants act as an ecosystem ‘liver’ filtering pollutants such as sulphur dioxide and nitrogen dioxide through their leaves and roots, while dense canopied trees trap particulate material that might overwise find its way into our lungs and even bloodstream. According to a study in the British Medical Journal, nearly 9 million deaths a year are attributable to air pollution and up to one in ten lung cancers. And it’s not just our health that air pollution is damaging – according to the Woodland Trust, “nitrogen air pollution directly affects many plants and fungi. It strips trees of their protective lichens and causes a fertiliser effect where grasses out-compete more delicate woodland flowers. This disrupts woodland ecosystems in ways we are only beginning to understand”.

However, not all plants are created equal when it comes to detoxing. All plants absorb carbon dioxide and then there are ‘hyperaccumulators’, the real workhorses which can absorb high levels of pollutants without being poisoned themselves. They absorb pollutants through their roots then either storing them or converting them to less harmful chemicals or vapor which is released into the air in a process called phytoremediation. This breaking down of toxins, heavy metals and contaminates is a biohack that we can employ on a huge scale to clear up toxic wastelands and within our own homes and gardens. So which plants do it best?

Planting a tree of any species is a very