RHS research over the last two decades has found that plants with high transpiration rates can help reduce flood risk and provide urban cooling and hairy-leaved plants capture particulate pollution, making them an important first defence as the climate crisis results in less frequent but heavier rainfall and flash flooding in our urban areas, increased average temperatures and high levels of pollution.
In a study published in
Landscape and Urban Planning, more than 400 participants were divided into two groups – one was given basic facts about environmental issues such as climate change and urban flooding while the other group was also given information about how to potentially manage those problems by growing plants with desirable traits, such as hairy leaves and high transpiration rates.
‘Action-related’ knowledge - whereby participants were offered solutions - significantly increased the likelihood of people changing their planting preferences in favour of varieties that could mitigate flooding and reduce air pollution. In addition, participants that were concerned about, or had experienced, the impacts of climate change were significantly more willing to select taxa (or species) that provided environmental benefits.
As a result of the research the RHS wants to work with growers and retailers to explore how labelling can inform planting choices, having last year launched its RHS Plants for Purpose project to organise the UK’s 400,000 cultivated plants according to benefit, such as flooding mitigation, air pollution capture, cooling, and support for wildlife. RHS scientists are developing the lists with the assistance of AI, starting with the traits identified as desirable in tackling a problem. RHS Plants for Pollinators relaunched in July and is available here:
www.rhs.org.uk/science/research/plants-for-pollinators
The RHS is also recommending gardeners look to plant the following this month where they might benefit:
| Benefit |
Trait |
Plant |
| Air pollution capture |
Semi evergreen with small leaves good for trapping particulate pollution e.g. roadside particles |
Elaeagnus × submacrophylla cultivars |
| Water management |
semi evergreen; tends to be fully evergreen in mild areas and towns and cities helping it to slow the flow or rainwater run-off |
Privet (Ligustrum species and cultivars) Note: Growing a larger hedge will mean a larger surface area, making it more effective
|
| Cooling and thermal regulation |
Native and has high transpiration rates/cooling potential when in leaf |
Hawthorn (Crataegus monogyna) |
| Pollinators |
Provide vital nectar in the winter months |
Hellebores - such as Helleborus × hybridus Harvington white speckled and Helleborus niger |
Professor Alistair Griffiths, RHS Director of Science, said: “This research shows that by delivering information in the right way we have the potential to empower the UK’s 34 million[1] adult gardeners to make a significant contribution in mitigating the effects of climate change. The RHS launched RHS Plants for Purpose precisely to help gardeners in their decision making and to highlight that the right plants in the right places for the right purposes can make a measurable difference. We want to work with industry to ensure that consumers are provided with clear, accessible labelling at the point of sale, empowering gardeners to make plant choices that help in the face of climate change.”
The research included work undertaken at the University of Reading led by Dr Caitlin McLaughlin, alongside Dr Jake Bishop and Dr Tijana Blanusa.
Dr Jake Bishop, University of Reading, said: “This is strong evidence that giving gardeners practical, solution-focused information can transform how they choose plants. By linking plant traits to real-world benefits like cooling, flood mitigation and capturing pollution, we are giving gardeners individual power to take meaningful action on climate resilience.”
ENDS
