Wandering jew
Tradescantia fluminensis
Family · Commelinaceae · Harmless
The glossy green fleshy mat that completely covers the floor of damp shady northern valleys and lets nothing else come up. A stem fragment with one node is enough to start a new patch.
Streams and ditches · Oak woods · Town and roadside
Also known assmall-leaf spiderwort, white-flowered wandering jew
How to tell it
Fleshy, translucent, brittle stems lying on the ground and rooting at every node. Alternate, oval, glossy leaves with a sheath clasping the stem. Small white flowers of three equal petals, in small clusters between two bracts. It forms continuous mats ten to thirty centimetres thick.
What it is confused with
No dangerous lookalikes known in the Iberian Peninsula.
What it is for
No use. It is among the hardest invaders to remove in Atlantic Europe precisely because it spreads only by fragments: pulling it carelessly spreads it. Where it covers the ground, the wood stops regenerating.
The law says
A listed invasive alien species in Portugal. Do not plant it, propagate it, or carry fragments on your boots.