The humble Cotoneaster franchetii is the best shrub for cleaning air polluted by car exhausts
Scientists report that the bushy, hairy-leafed Cotoneaster franchetii is the latest ‘super plant’ to help boost the environment and improve human health because of its special ability to fight pollution by trapping harmful airborne particles.
A new RHS science paper that looks at the effectiveness of hedges as air pollution barriers reveals that in traffic hotspots, the Cotoneaster franchetii (Franchet’s cotoneaster) is at least 20% more effective at soaking up pollution compared to other shrubs.
Poor air quality has been declared the largest environmental risk to UK public health and according to a recent RHS commissioned survey of 2,056 adults, air pollution affects one in three people (33%) in the UK.
However, only 6% take active steps in the garden to help alleviate it. In London, nearly six in 10 (59%) are affected by air pollution and almost a quarter (22%) of Londoners are ‘significantly affected’ but only 4% plant with pollution in mind.
Dr Tijana Blanusa , research lead for the paper and RHS Principal Horticultural Scientist, said: “On major city roads with heavy traffic we’ve found that the species with more complex denser canopies, rough and hairy-leaves such as cotoneaster were the most effective. We know that in just seven days a one metre length of well-managed dense hedge will mop up the same amount of pollution that a car emits over a 500 mile drive. We estimate the Cotoneaster franchetii traps 20% more emissions than other hedges we have tested so would be ideal along busy roads in pollution hot spots. For other areas where encouraging biodiversity and pollinators is key, a mix of different hedge species would be recommended.”
Read the paper: Blanuša T, Qadir ZJ, Kaur A, Hadley J, Gush MB. Evaluating the Effectiveness of Urban Hedges as Air Pollution Barriers: Importance of Sampling Method, Species Characteristics and Site Location. Environments. 2020; 7(10):81. doi.org/10.3390/environments7100081