Field Bindweed

Convolvulus arvensis L.

Family: Convolvulaceae.

Names:

Convolvulus is from the Latin convolvo and means to roll around or entwine and refers to the habit of the stems.
Arvensis is from the Latin arvum and means cultivated field and refers to the plants association with cultivation.
Field Bindweed refers to its habit of entangling other plants and binding the soil.

Other Names:

Bindweed
Common Bindweed
Cornbine (UK)
European Bindweed
Field Morning Glory
Hiranpandi (Hindi)
Lesser Bindweed
Morning glory (USA)
Small Flowered Morning Glory
Wild morning glory.

Summary:

A perennial vine with white or pink, trumpet shaped flowers in summer. It has arrow shaped leaves and long twining stems.

Description:

Cotyledons:

Two. Round 10-15 mm long with a 10-15 mm stalk. Tip indented. Base indented to squarish. Hairless. Obvious veins. Seedling has both a hypocotyl and epicotyl.

First leaves:

Grow singly at first being 10-20 mm long on a 10-20 mm stalk. Arrow shaped to triangular with an indented base. Long stalk. Tip rounded. Hairless.

Leaves:

Alternate. Does not form a rosette. Variable shape and size that depends on shading, defoliation, disturbance, moisture and nutrition.
Stipules - None.
Petiole - 5-25 mm long 1-2 mm wide.
Blade - Dark green, arrow shaped to triangular. 15-50 mm long, 10-30 mm wide. Edges smooth. Tip obtuse or with a small point. Base indented. Lobes at the base of the leaf often bent backwards or at right angles to the leaf. A few fine hairs, usually hairless when mature.
Stem leaves - Up to 60 mm long. Stalked. Longer and more pointed than early leaves. Smaller near the ends of stems. Few scattered hairs especially near edges.

Stems:

Up to 2000 mm long. Solid. Round or polygonal in cross section and may have spiral ridges. Twining and climbing. Prostrate forming a tangled mat on the ground. A few fine hairs. Branch from base and along their length. Cobweb hairs on young shoots that normally disappear with age.

Flower head:

Single flowers, pairs, or 4's arsing from the leaf axils, on 20-40 mm long stalks that exceed the length of the subtending leaf.

Flowers:

Pleasant odour. Close in dull conditions. Each flower only remains open for a day.
Bracts - A pair of opposite bracts, 10-25 mm long, are just above the middle of the leaf stalk.
Ovary - Hairless. Stigma lobes much shorter than style.
Sepals - 3-6 mm long. 2 outer ones shorter, oblong to elliptic, obtuse tip, very shortly hairy, may appear hairless (minutely ciliolate). Inner ones, circular, obtuse or blunt slightly notched tip, with a fine point.
Petals - Pink, white or white with pink, mid petal stripes or pink with red or white mid petal bands. Fused to form a funnel shape with shallow lobes. 20-30 mm diameter x 15-25 mm long.
Stamens - Slightly different lengths. Filaments with broadened bases and very fine hairs on the edges.
Anthers -

Fruit:

Globular, smooth, pointed capsule, bent back. About as long as sepals, 4 mm diameter. Has 2-4 seeds.

Seeds:

Grey brown, triangular to pear shaped, 3-5 mm long and slightly rough with tiny warts. One side is rounded and the other has a rounded central ridge. Prominent, reddish scar at the base. Hairless.

Roots:

White, deep, usually single taproot to 3000-9000 mm deep. Many horizontal roots, mainly 100-600 mm below the soil surface extending for some distance and with buds that give rise to aerial shoots. Creeping rootstock and rhizomes.
Cord like and fleshy.

Key Characters:

Hairless sepals.

Biology:

Life cycle:

Perennial. Germinates at any time but mainly in spring with less in summer and autumn. Grows rapidly over summer, producing 15-30 leaves and roots to 2000 mm deep over the next seven months. Some flower in late summer to autumn and others remain vegetative producing many lateral roots. Top growth dies back in winter. Growth from the roots and crowns appears during the late winter and early spring. Flowering occurs from late spring to early autumn. The plant dies back with the onset of cold weather.

Physiology:

Does not tolerate waterlogging.
Poor competitor for light.
Strong competitor for moisture and nutrients with its extensive, deep perennial root system.
Drought tolerant.

Reproduction:

By seed, rhizomes, rootstock and root and stem fragments

Flowering times:

November to January in SA.
Late spring to summer in NSW.
December to March in Perth.

Seed Biology and Germination:

The seed has a hard coat that allows it to remain dormant in the soil for at least 20 years and for over 50 years when stored indoors.
80% of seeds have a hard, impermeable seed coat. Dormancy can be broken by mechanical or chemical damage to the seed coat.
Up to 500 seeds per plant are produced.
The seed bank in established stands is around 2000 m-2.

Vegetative Propagules:

Rhizomes, rootstock and root and stem fragments.
Over 12 t ha-1 of roots were recovered in a Californian patch.

Hybrids:

Several biotypes exist with varying leaf and stem numbers, leaf shape, flower colour and shape and vigour.

Allelopathy:

Produces toxins which reduce the growth of companion species especially Amaranthus spp. or Prince of Wales Feather. This may account for some of its competitiveness.

Population Dynamics and Dispersal:

Spread by seed in agricultural produce and on machinery. Cultivation implements and earth moving machinery often spread root fragments.
Seed production is variable and is greatest under dry sunny conditions. In cool, wet or waterlogged areas, flowering may be minimal and fruit often contain no viable seed.
Viable seed passes through stock and birds. Manure is an important method of spread in horticultural areas, and migratory birds have been implicated in long distance dispersal.
Spread from expansion of the undisturbed root system may reach 10 metres per year.
Shoots from roots are very strong and may push through bitumen roads.

Origin and History:

Europe and Asia.
Probably in NSW by 1803.

Distribution:

ACT, NSW, QLD, SA, TAS, VIC, WA.
Occurs in all parts of Tasmania, but is less abundant in the Midlands.
No large infestations in WA.

Courtesy Australia's Virtual Herbarium.

Habitats:

Climate:

Humid and sub humid temperate areas up to sub alpine levels.
Moderate rainfall areas.

Soil:

Prefers fertile, deep and alkaline loams and sands, but tolerates a wide range of soil types.

Plant Associations:

Prefers open situations.

Significance:

Serious world wide weed.

Beneficial:

Fodder, but not highly valued.
Soaked plants used as a drink in India.
Root extract used as a purgative.
Associated with the sign of Cancer in astrology.

Detrimental:

Weed of cereal crops, orchards, vineyards, vegetables, gardens, cemeteries, stream banks, pastures, corn, sugar beet, railways and disturbed areas.
Difficult to remove from wheat because the seed is of similar size.
Host for viruses of potatoes, tobacco and tomatoes. Host for some insects and nematodes of agricultural significance.

Toxicity:

Suspected to cause photo sensitisation in stock.
Roots may be toxic to pigs.

Symptoms:

Gastroenteritis in pigs.

Legislation:

Noxious weed of NSW, SA, VIC and WA.

Management and Control:

Thresholds:

Cereal yields are reduced by 30-80% overseas.
May overwhelm young vines and trees.

Eradication strategies:

Repeated deep cultivation is required for a number of years. In one experiment, cultivation every 10 days during the growing season for four years was required to eradicate it.
Deep ploughing before flowering gives the greatest control. Tined implements should not be used because they are more likely to spread root fragments.
A number of herbicides provide good control but require repeated applications to control roots and seedlings from previously dormant seed. Picloram based herbicides applied at the budding stage are usually the most effective. Hormone herbicides, dicamba, glyphosate, linuron and fluroxypyr are used in various situations.
Effective control programs usually rely on a combination of herbicides, cultivation and competition. Lucerne is an effective competitor in suitable areas.
Flooding to a depth of 150-250 mm for 60-90 days is used overseas for control.

Herbicide resistance:

Some populations differ in their response to 2,4-D and glyphosate.

Biological Control:

A fungus Phomopsis convolvulus may have potential as a mycoherbicide. Other biocontrol agents have not been fully investigated.

Related plants:

Australian Bindweed (Convolvulus erubescens) has hairy, pointed sepals and no creeping rhizomes, the leaves tend to be less arrow shaped, the flowers tend to be pinker and smaller and it is less aggressive and more palatable.
Sweet Potato (Ipomoea batatas).

Plants of similar appearance:

Black Bindweed has a membranous sheath at the base of the petiole, the cotyledons are a different shape and the flowers are very different.
Greater Bindweed (Calystegia sepium) is generally larger, has the bracts just below the flower instead of half way along the flower stalk and tends to be restricted to towns.

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P155. Photos.

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P703. Diagram.

Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P304.

Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P555-556. Photo.

Hyde-Wyatt, B.H. and Morris, D.I. (1975). Tasmanian weed handbook. (Tasmanian Department of Agriculture, Hobart, Tasmania). P88. Diagrams.

Hyde-Wyatt, B.H. and Morris, D.I. (1980) The Noxious and Secondary Weeds of Tasmania. (Tasmanian Department of Agriculture, Hobart, Tasmania).P60-61. Diagrams.

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #345.1.

Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P538-539.

Meadly, G.R.W. (1965). Weeds of Western Australia. (Department of Agriculture - Western Australia). P117-119. Diagram. Photo.

Parsons, W.T. and Cuthbertson, E.G. (1992). Noxious weeds of Australia. (Inkata Press, Melbourne). P396-399. Diagram. Photos.

Wilding, J.L. et al. (1987). Crop weeds. (Inkata Press, Melbourne). P96-97. Diagrams. Photos.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.