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Cornfield Knotgrass

Polygonum rurivagum

Please keep in mind that it is illegal to uproot a plant without the landowner's consent and care should be taken at all times not to damage wild plants. Wild plants should never be picked for pleasure and some plants are protected by law.
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Plant Profile

Flowering Months:
Polygonaceae (Dock)
Life Cycle:
Maximum Size:
80 centimetres long
Fields, gardens, wasteland.

Pink, 5 petals
Small clusters (1 or 2) of flowers. Flowers may be pink or white.
A dark red or brown, 3-edged achene.
Very narrow, linear, pointed leaves, alternate along the stems. Usually found in limy fields.
Other Names:
Field Bindweed.
Frequency (UK):
Occasionally seen  

Other Information


Polygonum rurivagum, commonly known as field bindweed, is a species of flowering plant in the Polygonaceae family. It is native to Europe and Asia, but it has naturalized in many parts of the world, including North America. It is a climbing or trailing perennial vine that can grow up to 2 meters long. The leaves are arrowhead-shaped and the plant produces small, white or pink, funnel-shaped flowers in the summer. The plant spreads via underground runners and can be difficult to control, it is considered a weed in many areas and can damage crops and gardens. It is often found in fields, gardens, and waste areas. It prefers well-drained soils and full sun to partial shade to grow well, but it is tolerant of a wide range of growing conditions.


Cornfield knotgrass, also known as Polygonum rurivagum, is a plant species that belongs to the Polygonaceae family. It is a hardy and adaptable plant that can be found growing in a wide range of habitats, including meadows, pastures, roadsides, and agricultural fields. It is a popular plant among gardeners, owing to its attractive appearance and easy-to-grow nature.


Cornfield knotgrass is an annual or biennial herb that grows up to 80 cm tall. It has an erect stem with branched nodes, which are hairy and rough to the touch. The leaves are narrow and lance-shaped, with a prominent midrib and a pointed tip. The flowers are small and greenish-white, arranged in clusters at the tips of the stems. They bloom from June to October and are followed by small, triangular fruits.


Cornfield knotgrass is native to Europe and Asia but has been introduced to North America, where it is now considered a weed in some areas. It is a common sight in agricultural fields and other disturbed habitats, where it can outcompete native plant species and reduce biodiversity.


Cornfield knotgrass has a long history of use in traditional medicine, where it has been used to treat a wide range of ailments, including stomachaches, diarrhea, and respiratory infections. It is also used as a diuretic and astringent. However, there is limited scientific evidence to support these uses, and the plant should not be used without consulting a healthcare professional.

In addition to its medicinal uses, cornfield knotgrass has been used for centuries as a fodder crop for livestock. It is high in protein and minerals and is a valuable source of nutrition for animals. It can also be used as a green manure crop, where it is grown and then plowed under to enrich the soil.


Cornfield knotgrass is an easy-to-grow plant that is well-suited to a wide range of growing conditions. It prefers full sun and well-drained soil but can tolerate a wide range of soil types and moisture levels. It is a good choice for wildlife gardens, where it can provide food and shelter for insects and other small animals.


Cornfield knotgrass can be propagated from seed, which should be sown in the spring or fall. The seeds can be sown directly in the garden or started indoors and transplanted later. The plant self-seeds readily, so it can become invasive if not controlled.

Cornfield knotgrass is a hardy and adaptable plant that is well-suited to a wide range of growing conditions. While it has a long history of use in traditional medicine and as a fodder crop, its potential medicinal uses should be approached with caution. Nevertheless, it is a valuable addition to any garden or wildlife habitat, providing food and shelter for a wide range of small animals and insects.

More Information

While cornfield knotgrass has some potential medicinal uses, it should be noted that there is limited scientific evidence to support these claims. As with any herbal remedy, it is important to consult a healthcare professional before using it for medicinal purposes.

In addition to its use as a fodder crop, cornfield knotgrass is also used in some traditional cuisines. In Japan, it is known as yabukita and is used in soups, stews, and stir-fries. In China, it is used in traditional herbal teas and as a vegetable. In Europe, it has been used to make a type of beer called gruit, which was brewed before the widespread use of hops.

As a weed, cornfield knotgrass can be problematic in agricultural fields, where it can outcompete crops and reduce yields. It can also be a nuisance in garden beds, where it can spread rapidly if not controlled. However, it can be a valuable plant in disturbed habitats, where it can help stabilize soil and provide habitat for wildlife.

Another interesting feature of cornfield knotgrass is its ability to tolerate high levels of heavy metals in soil. This makes it a useful plant for phytoremediation, which is the use of plants to remove pollutants from contaminated soil. Cornfield knotgrass has been shown to be effective at removing metals such as cadmium, copper, and zinc from soil, making it a potentially useful tool for environmental cleanup efforts.

Furthermore, cornfield knotgrass is a host plant for several insect species, including the larvae of the common nettle-tap moth and the black-spotted prominent moth. These insects feed on the leaves and stems of the plant, and their presence can attract other wildlife to the area, such as birds and small mammals.

While cornfield knotgrass is not typically considered an ornamental plant, its attractive appearance and hardiness make it a useful addition to naturalistic or wildlife gardens. It can be used to provide structure and texture to planting schemes, and its green and white flowers can add interest to mixed borders.

One additional aspect of cornfield knotgrass is its potential as a source of bioactive compounds. Several studies have investigated the chemical composition of the plant and its potential uses in pharmaceuticals and other applications. For example, one study found that the plant contains high levels of rutin, a flavonoid that has antioxidant and anti-inflammatory properties. Another study found that the plant contains compounds that have antifungal and antibacterial activity.

In addition to its potential medicinal uses, cornfield knotgrass has been used for centuries in traditional textiles. The plant contains a natural dye that produces a range of colors, including yellows, browns, and greens. The plant fibers can also be used to make paper and other products.

Overall, cornfield knotgrass is a fascinating and multifaceted plant that has many potential uses and benefits. While it is not without its drawbacks, its hardiness, adaptability, and versatility make it a valuable addition to many different types of gardens and habitats. Whether used for conservation, horticulture, or research purposes, cornfield knotgrass is a plant that is sure to continue to capture the interest and imagination of people for many years to come.

Distribution Map

Reproduced by kind permission of the BSBI.

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