This section is from the book "British Wild Flowers - In Their Natural Haunts Vol2-4", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
Though a northern plant there is no evidence that this species is ancient, its present range being the Northern and Southern Temperate Zones in Europe, Siberia, N. Africa, temperate N. and S. America, Australia, and New Zealand. In Great Britain it does not grow in Cardigan, Roxburgh, Linlithgow, E. Highlands, the Northern Isles, but elsewhere it is general. It is found in Ireland.
Great Bindweed is a typical inland species growing in almost every hedge, and is common by the roadside, where it clambers over hawthorn and other hedgerow plants. Unlike the Small Bindweed, it is not associated in general with cultivated ground, though it may occur in the hedges enclosing cornfields.
The rambling, climbing habit of Great Bindweed, which needs the support of a hedge or similar aid to enable it to lead an aerial existence, is one of its most striking features. It has a long white creeping root, difficult to eradicate in gardens, hence the English names. The stems are numerous, twining, twisted, striate or finely furrowed, branched, the branches being alternate. The leaves are arrow-shaped or angular below, acute, alternate, stalked, smooth. The growing part revolves from right to left against the sun, revolving in two hours.
The flowers are white, bell-shaped, and large. The flower-stalks are 1-flowered, square-stalked, and the flowers are axillary. The bracts or leaflike organs enclose the calyx, and are cordate, veined, and purple. The flowers open for one day, and are not scented, but are open in the moonlight. The corolla is plaited in the bud. The calyx, which is 5-fid, is tubular. The limb of the corolla is scarcely divided, and the seeds are angular, but rarely produced.
The plant grows to a length of 6-10 ft. It flowers in July up till September. It is perennial, increasing freely by division of the roots.
The flowers are very large and conspicuous, but have no scent and no path-finders, so that they are little visited by insects. They do not close up when it is raining, though they contain honey. They close between 8 and 10 p.m., but are open when it is a moonlight night. The floral mechanism is as in C. arvensis. The honey is in a yellow ring at the base of the ovary. The style is twisted, as in some plants where the flowers are pollinated by crepuscular insects. It is visited by the Convolvulus Hawk Moth (Sphinx convolvuli), which has been found on the flowers in the evening. The ovary does not bend over after flowering, being protected by the large leaflike organs or bracts.
Ha/ictus, Megachile, Empis, Rhingia, creep into the base of the flower by day, and insert their probosces between slits between the filaments or anther stalks. Rhingia rostrata applies its labellae to the anthers, stigma, and corolla wall. Meli-gethes, Thrips, Podura, visit it by day. Wherever the Convolvulus Hawk Moth (Sphinx convolvuli) is common so is C. sepium. If the former is absent the latter may not produce seed at all.
The capsule splits open when ripe, the seeds being scattered around the parent plant.
Great Bindweed is a sand-loving plant growing mainly on sand soil, or sandy soil or sandy loam with a little humus.
Three fungi, Cystopus tragopogonis, Puccinia convolvuli, and Theca-phora hyalina, infest it, and the latter destroys the seeds.
A beetle Longitarsus exoletus, and several moths, the Convolvulus Hawk Moth (Sphinx convolvuli), Small Scallop (Acidalia emarginata), the Double-striped Pug (Eupithecia pumilata), Pterophorus penta-dactylus, Emmelesia trabealis, Spotted Sulphur (Agrophila sulphuralis), the Four-spotted (Acontia luctuosa), Small Mottled Willow (Caradrina exigua), Mottled Rustic (C. morpheus), Ebulea sambucalis, Bdellia somnulentella, feed on it.
Photo. B. Hanley - Great Bindweed (convolvulus Sepium, Br.)
Calystegia is from the Greek kalos, beautiful, and stego, cover, alluding to its habit of covering hedges, or the large bracts, etc. Septum is Latin for, of hedges.
The names by which Great Bindweed is known are numerous, e.g. Bearbind, Bedwind, Bell-bind, Bell-binder, Bell-bine, Bellwine, Bell Woodbind, Hedge Bells, Beswinor, Beswind, Bethwine, Common Bind, Bindweed, Great Bindweed, Bineweed, Great Bines, Convolvulus, Cornbind, Corn Lily, Creeper, Devil's Garter, Devil's Guts, Ground Ivy, Hellweed, Honey Suckle, Jack-run-in-country, Lady's Smock, Harvest, Hedge, White Lily, Lily-bind, Lily-flower, Milk Maid, Night-caps, Grandmother's, Lady's, and Old Man's Nightcap, Robin-in-the-hedge, White Smock, Wave Wine, Way Wind, Weather Wind, Weedbine, Wither Wine, With Wind, Withy Wind. It was called Devil's Guts because of the long creeping roots that every gardener knows.
The name Hedge Lily is thus whimsically explained by Turner: " There is a flower not unlyke unto a lylye in the herbe which is called convolvulus, it groweth among shrubbes and busshes and hath no savour, nether any little Chyves lyke saffrone as a lyly hath, only representing a lily in whytenes, and it is as it were an imperfect worke of nature learninge to make lilies". When expanded it was regarded as a sign of fine weather. It was called Devil's Garter because of its supposed association with the evil one. It is purgative in principle.
Essential Specific Characters: 220. Calystegia septum, Br. - Stem climbing, leaves sagittate, with blunt lobes, flower-stalks square-flowered, flowers white, campanulate, axillary, with two large bracts, enveloping the calyx.