Field bindweed Convulvulus arvensis Weed of the Week


Other common names, mostly obsolete, include lesser bindweed, European bindweed, withy wind (in basket willow crops), perennial morning glory, small flowered morning glory, creeping jenny, and possession vine. It is called leli in Punjabi.

Convolvulus arvensis (field bindweed) is a species of bindweed in the morning glory family, native to Europe and Asia. When unimpeded, wiry stems often grow more than 3 feet long and intertwine to form prostrate web-like mats or climb any nearby plant, fence or wall. It has perfected a whole arsenal of survival techniques that have ensured it is one of the most intractable species of weed.
Structure.

Leaves are most commonly arrow-shaped, 1/2 to 1 1/4 inches long, and are arranged alternately along the stem.
bindweed

Funnel-shaped, white or pinkish flowers, approximately 1 inch in diameter, are borne on stalks that grow in leaf axils.  Flowers have a light almond fragrance.  The nectar of the flowers attracts a large number of insect species. Several pink stripes are sometimes present on the underside of the flower, extending from the base of the flower to the tip of the petal.
bindweed flowers

The flower stalk also bears two tiny bracts 1 inch below the flower. Though most field bindweed seeds germinate by early summer, seeds can germinate anytime between early spring and late autumn. This variation in germination time is one of the strategies by which field bindweed ensures its survival. Seedlings may appear from seeds buried for up to 50 years. The longevity of the seeds providing another strategy of persistence.  bindweed seeds

Once the seedling is established the plant extends underground horizontally. The underground system may extend 30 square yards in a season and the vertical roots can penetrate to a depth of eighteen feet. New shoots may generate from the underground stems or from the roots. When the roots are cut the growth of new roots is promoted although the plant is temporarily weakened.  the plant has a rapid system to regenerate following damage. Once the shoot is cut a milky sap oozes from the cut and seals the cut forming a callus. Dormant buds near to the site of the cut are stimulated to generate new roots and stems. Therefore even if the plant is chopped into pieces each piece will form a new bindweed plant. It the plants are repeatedly cut the bush develops a multi-stemmed form generating multiple branches. If the stems are buried they can take root. If the plants are eaten  by animals they are stimulated to grow even faster. Flowers last only 1 day, and are produced throughout the summer. Freezing temperatures in autumn cause shoots to die back, although most roots remain intact. In the laboratory field bindweed has been shown to be able to find its way to a light source through a maze of blackened tubes.
Field bindweed produces a tap root which can penetrate up to 18 feet in depth. Many spreading roots grow laterally from the tap root, sometimes extending 30 feet. The extensive root system allows the plant to compete successfully with other plants and survive harsh conditions, such as drought and intense cold. Chemicals secreted by the roots are thought to interfere with the germination of some crop seed. Buds develop on the lateral roots, producing underground rhizomes and aboveground shoots.
bindweed roots 2

Field bindweed rhizomes and stems break easily, and when fragmented, underground plant parts will produce new plants.
One plant can produce as many as 14 shoots in 1 year, each of which grows 1 ½ – 4 ½ feet in the first season. Those shoots shaded by other plants will adopt a climbing habit to reach light. Each plant is capable of producing 25-300 seeds, which generally fall near the parent plant. However, seeds can also be carried by water, in mud stuck to
vehicles or shoes, and by birds or other animals that consume them. Due to an extremely hard seed coat, some seeds can
remain viable in the soil for more than 50 years.

Problems with Bindweed
Although it produces attractive flowers, it is often unwelcome in gardens as a nuisance weed due to its rapid growth and choking of cultivated plants. It was most likely introduced into North America as a contaminant in crop seed as early as 1739, as an invasive species. Plants typically inhabit roadsides, grasslands and also along streams. Its dense mats invade agricultural fields and reduce crop yields.
In one of the tales collected by The brothers Grimm, Our Lady’s Little Glass, this flower is used by The Virgin Mary to drink wine with when she helps free a wagoner’s cart.  Obviously she didn’t drink wine in the quantities that most of us do. The story goes on to say that “the little flower is still always called Our Lady’s Little Glass.”

. Control of bindweed
High light conditions are optimal for field bindweed and it is not seen in heavily shaded conditions thriving in areas with bare soil or sparse plantings. Consequently blocking the plants from reaching light is at the core of many of the strategies for its control.  Mulch can help prevent bindweed growth by blocking light. Desirable plants that produce early, vigorous growth can create a shady environment for the prostrate-growing field bindweed and put it at a competitive environment for the prostrate growing of field bindweed putting it at a disadvantage. Young seedlings can be destroyed when cut several inches below the soil. Hoeing, digging, or tilling more mature field bindweed every 1-2 weeks for several seasons can reduce plant vigour, and eventually allow for some control to be achieved. Personally I have found fighting with this plant for dominance of the garden to be a constant battle. The best that I could attain was a truce, but if I neglected to watch for the small shoots I would be under attack again. Whilst I think the flowers are very pretty and delicate the plant will completely smother any plant it can utilise for support. Basically it is a thug.
bindweed seedling

Ecological importance
Many insects visit field bindweed for pollination. The plant has been used as a remedy for spider bites and for female problems, among other things (what a lovely euphemism, I suspect it doesn’t mean pain from wearing high heels or sitting next to a sweaty bloke who has never used deodorant on the tube). Its stems have been used for cordage, (let us hope they didn’t throw the cord on the soil when they had finished with it) and its leaves and stems have properties that can destroy mosquito larvae. Although some grazing animals will consume field bindweed, it produces poisonous alkaloids and can accumulate toxic levels of nitrates. The plant can serve as a host for several viruses that affect potatoes, tomatoes and other crops. Its presence in crops can also interfere with harvest and significantly reduce yields.

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