Calystegia sepium (Hedge bindweed)

Family Convolvulaceae. Distributed widely throughout the temperate zone of the Northern and Southern Hemispheres.

Perennial, herbaceous, climbing plant up to 300 cm tall. Leaves triangular or triangular-ovate with an acute apex, glabrous, petiolate, arranged alternately. Flowers solitary, white or pale pink, up to b cm in diameter. Bracts up to 3 cm long. Flowers in May. Fruit - a rounded capsule.

This is a widespread, persistent weed that is difficult to eradicate. You have almost certainly seen it — if not in your own garden, then in a neighbor's — and it is commonly called bindweed. It twines around any supports, including other plants, and its white, long rhizomes strip them of every last nutrient. Bindweed spreads through the garden at an enormous rate, and every piece of rhizome, even the smallest, immediately produces a new shoot. So there is no need to worry about propagation; Calystegia handles that perfectly on its own. It requires no care, of course; and don't worry about flowering — you will be admiring it all summer.