Swansea & Gower invasive plant guide
SwanseaWeed Control

What the service covers

  • Free initial quote from your photos to help confirm it is japanese knotweed
  • Mapping the stand and its edges before any work starts
  • Containment so roots, seed and soil don't spread further
  • The lightest method that works: pulling, cutting, digging, or precise herbicide where that is the safer option
  • Return visits and written records until regrowth stops

How to recognise it

  • Bamboo-like hollow stems, green with purple or red speckles, 2–3m tall by midsummer
  • Shield or heart-shaped leaves in a clear zig-zag pattern along the stem
  • Creamy-white flower tassels in late summer
  • Red asparagus-like shoots pushing through soil, tarmac and cracks in spring
  • Dead orange-brown hollow canes standing through winter

Season: Shoots March–April, peak growth June–August, canes die back brown in winter

Where japanese knotweed turns up locally

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Pins show general areas and publicly reported locations, not individual properties.

Local facts

Heaviest along the Tawe corridor, the Clyne and Cadle brooks, disused railway land in Landore and Morriston, and the back lanes of Brynmill, Uplands and Sandfields.

It almost never spreads by seed here. It spreads when rhizome or stem fragments are moved — fly-tipped garden waste, soil moved during building work, strimming, or river water carrying fragments downstream.

Legal status: Schedule 9, Wildlife and Countryside Act 1981. It is an offence to plant it or cause it to grow in the wild. Allowing it to spread onto a neighbour's land can be a private nuisance, and cut material is controlled waste under the Environmental Protection Act 1990.

Areas we cover for japanese knotweed

Full japanese knotweed guide

News & advice

All local news