The Redshank is a perennial plant

Perennial plant

A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...

 from the Knotweed family Polygonaceae

Polygonaceae

Polygonaceae is a family of flowering plants known informally as the "knotweed family" or "smartweed family"— "buckwheat family" in the United States. The name is based on the genus Polygonum and was first used by Antoine Laurent de Jussieu in 1789 in his book, Genera Plantarum. The name refers...

. It is also called Persicaria, Redleg, Lady's-thumb, Spotted Ladysthumb, Gambetta, and Adam's Plaster in Newfoundland. Native to Europe, it is an invasive species in the Great Lakes

Great Lakes

The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...

 region where it was first spotted in 1843.

Species

There are three varieties known:

• Polygonum persicaria var. angustifolium Beckh.
• Polygonum persicaria var. persicaria
• Polygonum persicaria var. ruderale (Salisb.) Meisn.

Synonyms include P. maculata, P. persicaria, P. ruderalis, P. ruderalis, P. vulgaris, P. dubium, P. fusiforme, P. minus and P. puritanorum.

Growth

It grows up to 1 m high, and has narrow, lancet-shaped leaves

Leaf

A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

 8–10 cm long. The leaves often have a brown or black spot. The white, pink or red flower

Flower

A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...

s are in dense panicle

Panicle

A panicle is a compound raceme, a loose, much-branched indeterminate inflorescence with pedicellate flowers attached along the secondary branches; in other words, a branched cluster of flowers in which the branches are racemes....

s and flower from early summer to late autumn.

It is native to Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 and Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, where it can be mistaken for Polygonum minus, but P. minus has narrower leaves, usually less than 1 cm wide, while its ear is slimmer.

It has been introduced to North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 and is naturalised in all mainland states, being found along roadsides, riverbanks, and on fallow ground. In the USA, it is very similar to Pennsylvania smartweed

Polygonum pensylvanicum

Polygonum pensylvanicum is a species of flowering plant in the buckwheat family, Polygonaceae, that is native to eastern North America. Common names include Pinkweed, Pink Knotweed, Smartweed, and Pennsylvania Smartweed....

, but Redshank has a fringe of hairs at the top of the ocrea, something which Pennsylvania smartweed lacks.

Cultivation and uses

This plant contains persicarin and tannin

Tannin

A tannin is an astringent, bitter plant polyphenolic compound that binds to and precipitates proteins and various other organic compounds including amino acids and alkaloids.The term tannin refers to the use of...

s. In medicine

Medicine

Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....

, Redshank is used against diarrhoea and infection

Infection

An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

s. The leaves and young shoots may be eaten as a palatable and nutritious leaf vegetable

Leaf vegetable

Leaf vegetables, also called potherbs, green vegetables, greens, leafy greens or salad greens, are plant leaves eaten as a vegetable, sometimes accompanied by tender petioles and shoots...

. It is often seen as a weed and rarely cultivated. A yellow dye can be produced from this plant with alum used as a mordant

Mordant

A mordant is a substance used to set dyes on fabrics or tissue sections by forming a coordination complex with the dye which then attaches to the fabric or tissue. It may be used for dyeing fabrics, or for intensifying stains in cell or tissue preparations. The term mordant comes from the Latin...

.