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Persicaria hydropiper
Also called Marshpepper smartweed, Marshpepper Knotweed, Waterpepper
Water pepper is an annual herb that grows in damp soil, shallow water and along stream banks, prized in Japan as a pungent leafy garnish. It is easiest grown in moist, partly shaded spots.
Persicaria hydropiper (syn. Polygonum hydropiper), also known as water pepper, marshpepper knotweed, arse smart or tade, is a plant of the family Polygonaceae. A widespread species, Persicaria hydropiper is found in Australia, New Zealand, temperate Asia, Europe and North America. The plant grows in damp places and shallow water. Cultivated varieties are eaten in East Asia for their pungent flavor.
Water pepper has several active ingredients. Two bicyclic sesquiterpenoids are present, polygodial (tadeonal, an unsaturated dialdehyde with a drimane backbone), and warburganal, which gives it its pungent taste. The plant also contains rutin, a source of the bitter taste impression.
Water pepper contains an essential oil (0.5%) which consists of monoterpenoids and sesquiterpenoids: α-pinene, β-pinene, 1,4-cineol, fenchone, α-humulene, β-caryophyllene, trans-β-bergamotene. Carboxylic acids (cinnamic, valeric and caproic acid) and their esters were present in traces. The composition depends strongly on genetic factors.
Water pepper is eaten in Japan, where it is known as tade (蓼), or more specifically, yanagi tade (柳蓼). The leaves of cultivated plants are used as a vegetable, as the wild type has a far more pungent taste. The herb is usually sold in markets as seedlings. Young red sprouts are known as beni-tade (紅蓼), and are used to garnish sashimi, tempura, and sushi. It is popular for summer cooking. The seeds may also be added to wasabi.
Amphibious Bistort · Pink Headed Knotweed · Chinese Knotweed · Curlytop knotweed · Redshank · Persicaria microcephala · Small water-pepper · Vietnamese Coriander · Pinkweed · Asiatic Tearthumb · Dotted Smartweed · Persicaria tinctoria
Text excerpted from the Wikipedia article Persicaria hydropiper by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.
