Invasive plants to take root at RHS Chelsea Flower Show


A garden of invasive plants is being developed at the RHS Chelsea Flower Show by a national trade body, to emphasise an important message to visitors.

Plants including buddleia, bamboo and montbretia might be a common sight in gardens across the country.

But they are among a number of non-native species, including Japanese knotweed, that ‘escape’ from gardens up and down the UK – and it’s a growing problem.

To raise awareness of the issue, experts from the PCA’s Invasive Weed Control Group are to showcase 14 of the good, the bad and the ugly invasive non-native plants which are currently thriving in gardens across the country.

The ‘Enemy Within’ garden will be located within the Discovery Zone in the Great Pavilion at the RHS Chelsea Flower Show, which takes place in May.

Professor Max Wade, chair of the PCA’s Invasive Weed Control Group, said: “Despite having more than 100,000 different plants available to gardeners in the UK, there is still a thirst for novel species.

“As a result, nurseries and garden centres have hundreds of new plants for customers to buy and plant in their gardens.

“Some are bred in nurseries, while others are newly discovered from across the world.

“Of course, all these new plants will have passed through appropriate importation checks and controls in relation to plant pathogens and pests, but we need to consider if any has the potential to become one of tomorrow’s invasive weeds.

“We know from studies of today’s invasive weeds that it can take decades to become a national problem after escaping from gardens.

“For instance, giant rhubarb was first seen outside of gardens in 1908 and it wasn’t until about the turn of the century that it became invasive, while Japanese knotweed took from 1886 to around 1940 to start its ascendancy.

“Based on this, we should consider that not only is tomorrow’s Japanese knotweed growing in gardens today, but we are busy planting the follow-on generation to perpetuate the process.

“The PCA’s Invasive Weed Control Group (IWCG) is the front line in combating invasive weeds in the UK and Ireland and recognises that prevention is a whole lot better than the large-scale effort needed to keep giant hogweed, giant rhubarb and Japanese knotweed invasions under control.

“Part of the challenge is to spot those species that have the makings of a problem for future generations.”

Visitors to the PCA stand will be able to see examples of various invasive plants in a garden setting to demonstrate how easy it is for these plants to fit in unknowingly.

The exhibit will also provide insights, education and guidance about the plants including identification, assessing risk, pathways of spread, preventative measures, necessary management approaches and control measures.

Professor Wade added: “Gardeners and horticulturists can make a valuable contribution to reducing the serious impact of invasive non-native plants environmentally, economically and socially.

“The aim of the exhibit is to help them to adopt informed, responsible and proactive approaches to the challenges posed, with the opportunity to talk to experts in this field and ask any particular questions about invasive plants directly.”