Hedge bindweed (Calystegia sepium) stems can grow 3m (10ft) long, either by trailing across the ground or, if given something to climb, by twining their way upwards. Its heart-shaped leaves grow up to 12cm (5in) long. Funnel-shaped flowers are about 5cm (2in) wide and appear from June to September; they are usually white but can also be pale pink with a white centre and five white stripes. After flowering, rounded capsules form, each containing up to four oval-shaped brown seeds about 3mm (⅛in) long.
The stems die back in autumn, leaving just the rhizomatous root system underground, ready to produce new shoots in spring. Established plants generally have a tangled mass of pale roots near the surface, with some longer ones potentially reaching as deep as 4m (13ft).
Field bindweed (Convolvulus arvensis) is smaller and less vigorous than hedge bindweed. Its trailing or twining stems don’t usually extend beyond 1m (3ft). Its oval to arrow-shaped, grey-green leaves grow up to 6cm (2.5in) long. Funnel-shaped flowers are often pale pink, but can also be pink with a white centre and stripes, or plain white. Flowers are about 2cm (¾in) wide and appear from June to September. Its seeds and roots are similar to those of hedge bindweed.