With spring in full swing, Oxfordshire gardeners have been warned about two invasive species.
National trade body Property Care Association has urged people to look out for Japanese Knotweed and Himalayan balsam.
Daniel Docking, technical manager at the Property Care Association, 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.”
Daniel Docking, technical manager at the Property Care Association (Image: Property Care Association) Japanese Knotweed, introduced in the 19th century, can cause issues as its root system expands, especially near built structures.
It 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.
Japanese Knotweed (Image: Property Care Association) 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.
Himalayan balsam (Image: Property Care Association) 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 Property Care Association, said: “Property Care Association 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.”