Calystegia sepium

Calystegia sepium (hedge bindweed, Rutland beauty, bugle vine, heavenly trumpets, bellbind, granny-pop-out-of-bed and many others) is a species of flowering plant in the family Convolvulaceae. It has a subcosmopolitan distribution throughout temperate regions of the North and South hemispheres.

Description
Hedge bindweed is an herbaceous perennial that twines in a counter-clockwise direction to a height of up to 3 m. The leaves are arranged alternately on the spiralling stem; they are dull green above and paler below, simple and sagittate (arrowhead shaped), 5–10 cm long and 3–7 cm broad.

The flowers are white, sometimes with pink windows, produced from late spring to the end of summer (between July and September in northern Europe). The buds are enclosed by large (2 cm long), ovate-lanceolate, green bracteoles with keels and burgundy margins; during anthesis they do not (or scarcely) overlap. The open flowers are trumpet-shaped, 3–7 cm diameter. After flowering, the fruit develops as an almost spherical capsule, which is hidden by the bracts. It is 1 cm in diameter, containing two to four large, dark brown, or black seeds that are shaped like quartered oranges.

The plant thrives in hedges, fields, borders, roadsides and open woods.

Hedge bindweed is toxic, containing calystegine alkaloids.

Identification
There are several species of Calystegia which occur in similar habitats and can be difficult to distinguish, especially when not in flower. It is common practice in Britain to treat C. sepium, C. silvatica and C. pulchra as an aggregate, usually recorded as "C. sepium agg.", whenever identification is uncertain. The use of this term sometimes creates confusion about which taxon is being discussed.

The best way to separate hedge bindweed (sepium) from the other taxa is by the bracteoles, which subtend the flower and wholly or partially encompass the sepals. Hedge bindweed has two rather long, narrow bracteoles which do not touch each other, whereas both large bindweed and hairy bindweed have shorter, wider bracteoles which overlap where they meet.

Taxonomy
Other vernacular names include greater bindweed, bearbind, hedge convolvulus, hooded bindweed, old man's nightcap, wild morning glory, bride's gown, wedlock (referring to the white gown-like flowers and the binding nature of the vine), white witches hat, belle of the ball, devil's guts and hedgebell. A common childhood pastime in the UK is to 'pop' the flowers from the sepals while chanting "Granny, granny — pop out of bed".

Several regional subspecies are accepted:
 * Calystegia sepium subsp. americana. North America.
 * Calystegia sepium subsp. angulata. North America.
 * Calystegia sepium subsp. appalachiana. Eastern North America.
 * Calystegia sepium subsp. erratica. North America.
 * Calystegia sepium subsp. limnophila. Southern North America.
 * Calystegia sepium subsp. roseata. Western Europe, coasts. Flowers pink.
 * Calystegia sepium subsp. sepium. Europe, Asia.
 * Calystegia sepium subsp. spectabilis. Siberia. Flowers often pinkish.

As a weed
While appreciated for its flowers, C. sepium can grow as a vigorous weed plant, and is able to overwhelm and pull down cultivated plants including shrubs and small trees. It is self-seeding (seeds can remain viable as long as 30 years), can rapidly regrow into whole plants from individual pieces such as discarded roots, and the success of its creeping rhizomes (they can be as long as 3 - 4 m) cause it to be a persistent weed and have led to its classification in some American states as a noxious weed.

C. sepium is highly sensitive to glyphosate, a systemic herbicide, but eradication may require several doses.

Similar species

 * Calystegia silvatica, giant bindweed, is sometimes treated as a subspecies of C. sepium
 * Convolvulus arvensis, field bindweed, is a similar vine with much smaller features. The rear margin leaf projections are sharp.
 * The leaves of Ipomoea pandurata, wild potato vine, are shaped like a heart, not like an arrowhead.