Wild buckwheat, Polygonum convolvulus

Life Cycle

Annual

Propagation

Reproducing only by seed.

Stems

Stems 5 cm to more than 2 m long, slender, prostrate or twining vine-like over other plants or any available support, with a short ocrea (membranous sheath) (a) at each node (joint).

Leaves

Leaves alternate (1 per node), arrowhead-shaped with pointed basal lobes (b) and elongated slender tips (c).

Flowers and Fruit

Flowers (d) small, 5 mm across, with 5 greenish to whitish sepals (no petals), in small clusters at tips of short branches or from axils of leaves (C); “seeds” dull black, 3 mm long, pointed at both ends but sharply triangular in cross-section and often partly or wholly enclosed by the dry sepals even after shattering from the plant. Flowers from July to August.

Roots and Underground Structures

Fibrous root system.

Habitat

Wild buckwheat is a common weed in cultivated fields and gardens throughout all of Ontario and its “seeds” frequently contaminate small grains.

Competitiveness

Corn yield loss (%)*: 2 % at 1 plant/m2 10 % at 5 plant/m2 Soybean yield loss (%)*: 4 % at 1 plant/m2 15 % at 5 plant/m2 *assumes that the weed has emerged with the crop and has been left uncontrolled all season.

Distinguishing Features

It is distinguished from all other weedy members of the Smartweed Family by its twining stems, its arrowhead-shaped leaves, and its seedling usually having longer cotyledons (e) (7 - 33 mm) long. It is distinguished from Field bindweed by its annual root system with thin, downward-tapering taproot (f), the presence of an ocrea (a) around the stem at each node (joint), its very small, short-stalked greenish flowers (d), borne in the axils of leaves (C) or in clusters along short branches, and its dark, sharply triangular seeds.

Toxicity

Wild buckwheat is not known to be toxic.

Human Health Issues

Wild buckwheat is not a known allergen.

Forage Quality

No information exists at this time.

Species Benefits

No information available at this time.

Often Mistaken For

Field bindweed (SONAR)

Power Ranking Corn

Power Ranking

↑ 21

 

Power Ranking Soybeans

Power Ranking

↑ 31

 

Biological Control

Currently none available for this weed. For the latest research on biological weed control: http://res2.agr.ca/Lethbridge/weedbio/index_e.htm#toc

Biopesticide Control

Currently none available for this weed in corn and soybean.

Herbicide Resistance

There are no known cases of herbicide resistance to this weed in Canada. For more information on weed resistance: http://www.plant.uoguelph.ca/resistant-weeds/


Figure #1.

Wild buckwheat: A. Base of plant. B. Portion of stem twing around another stalk. C. Section of stem with leafstalk, ocrea and 2 flowers.


Figure #2.

Cotyledons of wild buckwheat.


Figure #3.

Wild buckwheat at the 1-leaf stage.


Figure #4.

Leaves and flowers of wild buckwheat.


Figure #5.

Mature wild buckwheat.