Start of growth season sparks call for Wigan gardeners to act now on invasive plants

Experts at national trade body the Property Care Association (PCA) are advising gardeners to assess beds and borders, waterside and wild areas in a bid to ensure early identification.

Japanese Knotweed can be a particular problem in urban areas, while Himalayan balsam can quickly infest wasteland and the banks of rivers, streams and canals.

Daniel Docking, Technical Manager at the PCA said: “We’re at the start of the active season for invasive plant species, so it’s the ideal time to identify any affected areas and put biosecurity or remediation plans in place.

“These plants are quick to shoot up and block sunlight from reaching anything underneath, creating a canopy that stops native plants from getting a look in.

“Catching them early helps prevent spread - especially through contaminated soil, footwear or equipment - ensuring treatments are effective and under control from the start.”

Japanese Knotweed, introduced in the 19th century, can cause problems as its root system expands, especially when growing near built structures. The plant can push up through asphalt surfaces such as car parks and driveways, while its rhizomes (a below ground stem which spreads the root network) can interfere with underground infrastructure such as drainage pipes, cabling and water pipes.

Himalayan balsam favours moist, semi-shaded areas near slow-moving watercourses and wasteland where it will outcompete native plants. It can impact waterways by leaving riverbanks exposed to erosion following winter dieback or increase summer flooding due to constricted water flow. It spreads through self-setting seeds, but uprooted or cut plants can re-root or re-sprout from nodes on the stem.

Sarah Garry, Chief Executive of the PCA, said: “PCA members who specialise in invasive weeds can play a crucial role in identifying emerging Japanese Knotweed or Himalayan balsam, as well as working with gardeners to put a plan for eradication and remediation in place.

“UK laws impose responsibilities on landowners to manage ‘listed’ (Schedule 9) species on their property.

“We’d advise anyone with concerns about invasive plant species in their garden to visit our website for further information and to find a PCA member who will have the training, knowledge and experience to help tackle these issues.”

PCA has a specific guidance note for gardeners, which can be found at: Gardeners & Invasive Weeds | PCA Best Practice Guidance