West Swansea · Severe pressure
Clyne Valley & Blackpill
The city's biggest single invasive management challenge. Rhododendron has taken large blocks of former estate woodland; balsam lines the brook the length of the valley.
Streets and places to watch
- Clyne Valley Country Park
- Blackpill
- Mayals Road
- Clyne Gardens
- old Swansea–Mumbles railway line
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
Rhododendron ponticum
A Victorian garden shrub that has swallowed large parts of Clyne Valley and the Gower woodlands, turning ancient woodland floor into bare, dark, sterile ground.
Evergreen, flowers May–June
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
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