Swansea & Gower invasive plant guide
SwanseaWeed Control

What the service covers

  • Free initial quote from your photos to help confirm it is giant hogweed
  • 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

  • Enormous — 3 to 5m tall when flowering
  • White umbrella-shaped flower heads up to 60cm across
  • Thick green stems with purple blotches and coarse white bristles
  • Huge jagged, deeply divided leaves up to 1.5m wide

Season: Growth from April, flowers June–July, seeds August

Where giant hogweed turns up locally

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

Local facts

Scattered along the lower Tawe, around Llansamlet and parts of the Loughor estuary fringe.

By seed only — up to 50,000 per plant, carried far by watercourses.

Legal status: Schedule 9, Wildlife and Countryside Act 1981. Offence to plant or cause it to grow in the wild. Occupiers may also face public liability claims where the public are injured.

Areas we cover for giant hogweed

Full giant hogweed guide

News & advice

Advice article

Giant Hogweed in Swansea: Legal and Property Concerns

Giant hogweed in Swansea: understand Welsh legal duties, sap safety, and selling or mortgage concerns, with practical advice on surveys and safe control.

July 2025 · Swansea Bay News

Swansea, Neath and Llanelli named among Wales's worst knotweed hotspots

New figures from the national knotweed heatmap put Swansea city third in Wales with 936 verified sightings, Llanelli fourth with 693 and Neath sixth with 396. Wales as a whole records more than triple the knotweed density of England — which is why early reporting matters so much here.

Ongoing · Swansea Council

Swansea Council's knotweed treatment service is open for quotes

The council offers a paid treatment service for private land affected by Japanese knotweed, built on more than 20 years of treating its own land. Request a quote online and they aim to respond within 10 working days. Knotweed on council land should be reported to the nature team instead.

Ongoing · Swansea Council

Sign up for the council's knotweed email updates

Swansea Council runs a knotweed updates email list alongside its treatment FAQs — covering what to expect after spraying (die-back in about 14 days), safety around children, pets and ponds, and how repeat treatments over up to five years bring a stand under control.

September 2023 · Wales Online

North Hill case shows why knotweed between gardens needs early action

A Pleasant View Terrace homeowner spent over a year trying to get knotweed spreading from a neighbouring property contained. Knotweed crossing a boundary is a private legal matter — documenting it early and getting both owners into a treatment plan is far cheaper than a dispute.

All local news