BETTING ON HEDGES

Dr Tijana Blanusa, who leads the RHS’s research into the environmental benefits plants can offer, explains how hedges can improve pollution

Barriers like hedges can improve some aspects of air quality. This is because when airborne particulate matter, PM (tiny particles floating in the air due to transport or industrial emissions) are deposited on plant surfaces like leaves and bark, it can reduce their concentration in the air.

For the maximum benefit grow large, dense hedges to get the biggest surface area on which to trap pollution. Aim for at least 1.5m high and 1m deep. Plants with rough, hairy or scaly leaves tend to trap more particles. Evergreen species also provide a year-round barrier.

Some examples include Elaeagnus x submacrophylla (with hairy and rough leaves), common yew and Western red cedar, Thuja plicata.

Hedges also provide other environmental services. These include reduction of storm-water runoff, cooling and warming building insulation if positioned near houses, biodiversity support and noise mitigation. Find out more at bit.ly/hedges-choices