Polygonum coccineum

Muhl. ex Willd.

Water smartweed

PolygonaceaeLeavesSeeds/NutsPotential hazards — see below
Caution — Parts of this plant may be toxic or require specific preparation. Verify with multiple sources before consuming.
Polygonum coccineum
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(c) Ryan Sorrells, some rights reserved (CC BY)
Polygonum coccineum
iNaturalist · cc-by-nc
(c) cgbb2004, some rights reserved (CC BY-NC)
Polygonum coccineum
iNaturalist · cc-by-nc
(c) cgbb2004, some rights reserved (CC BY-NC)

What to Eat

Edible parts: Leaves, Seeds

Young shoots are collected in spring and used cooked. Seeds can be eaten raw or cooked, though they are small and fiddly to work with.

Known Hazards

Although no specific mention has been made for this species, there have been reports that some members of this genus can cause photosensitivity in susceptible people. Many species also contain oxalic acid (the distinctive lemony flavour of sorrel) - whilst not toxic this substance can bind up other minerals making them unavailable to the body and leading to mineral deficiency. Having said that, a number of common foods such as sorrel and rhubarb contain oxalic acid and the leaves of most members of this genus are nutritious and beneficial to eat in moderate quantities. Cooking the leaves will reduce their content of oxalic acid. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition.

Where to Find It

It is a temperate plant.

North America, USA,

Countries: Antigua & Barbuda, Barbados, Bahamas, Belize, Canada, Costa Rica, Cuba, Dominica, Dominican Republic, Grenada, Guatemala, Honduras, Haiti, Jamaica, St Kitts & Nevis, St Lucia, Mexico, Nicaragua, Panama, Puerto Rico, El Salvador, Trinidad & Tobago, United States, St Vincent

How to Identify

A perennial herb reaching 0.5 m tall, hardy to UK zone 5. Hermaphroditic flowers are insect-pollinated. Grows in light sandy, medium loamy, or heavy clay soils across a range of pH levels from mildly acidic to mildly alkaline. Tolerates semi-shade or full sun and thrives in wet conditions, even growing in water.

How to Grow

A water plant, succeeding in shallow water or a bog garden. Tolerates most soils but repays generous treatment. The stems of this plant root at the nodes wherever they come into contact with the soil. Plants seem to be immune to the predations of rabbits.

Propagation: Sow seed in spring in a cold frame; germination is generally free and easy. Once seedlings are large enough to handle, prick them out into individual pots and plant out during summer if they have reached sufficient size, or overwinter in a cold frame and plant out the following spring after the last expected frosts. Division can be done in spring or autumn and is very straightforward — larger divisions can go directly into permanent positions, while smaller ones do better potted up and grown on in light shade in a cold frame until well established before planting out in late spring or early summer.

Medicinal Uses

None known

Other Uses

None known Special Uses

Wikipedia

Source ↗

A perennial herb reaching 0.5 m tall, hardy to UK zone 5. Hermaphroditic flowers are insect-pollinated. Grows in light sandy, medium loamy, or heavy clay soils across a range of pH levels from mildly acidic to mildly alkaline. Tolerates semi-shade or full sun and thrives in wet conditions, even growing in water.

Notes

There are about 50 Polygonum species.

Names & Synonyms
P. muehlenbergii. (Meisn.)Wats. Persicaria muehlenbergii. (Meisn.)Small.
References (2)
  • Enum. pl. 1:428. 1809
  • Plants for a Future database, The Field, Penpol, Lostwithiel, Cornwall, PL22 0NG, UK. http://www.scs.leeds.ac.uk/pfaf/

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