Mile-a-minute vine. Also known as Polygonum baldshuanicum, this has long wiry stems sparsely clad with smallish leaves. The flowers are long airy sprays of creamy white bracts that almost cover the plants from midsummer to autumn. Plants grow at a tremendous rate, and can put on over 4m (13ft) in a year, which makes them ideal for covering eyesores like outbuildings, or screen walls, quickly.