North-west Swansea · High pressure
Townhill, Penlan & Cwmbwrla
Steep amenity banks between estates are rarely inspected, so knotweed stands grow large before anyone reports them. Cadle brook carries balsam downhill.
Streets and places to watch
- Townhill Road
- Portmead
- Blaen y Maes
- Carmarthen Road
- Cadle
These are the corridors where growth is most often recorded — lane walls, verges, brook banks and cleared plots. Individual gardens are not listed.
Towns, villages and places in this area
Each place has its own local guide with a map, area facts and the plants to watch for.
What grows here
Japanese knotweed
Swansea is one of the worst-affected places in Britain. Knotweed dominates back lanes, railway embankments, riverbanks and derelict plots across the city, and it is the weed most likely to affect a mortgage or a sale.
Shoots March–April, peak growth June–August, canes die back brown in winter
Himalayan balsam
The pink-flowered annual that lines almost every stream in Swansea. One plant throws up to 2,500 seeds and the seed floats, so a single upstream patch reseeds miles of bank.
Germinates March, flowers June–October, dies back with first frost