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Persicaria tinctoria, known as Chinese indigo, Japanese indigo or dyer's knotweed, is a tender annual grown mainly for its leaves, which yield indigo dye. It needs warm, moist conditions and a long growing season to produce good leaf.
Persicaria tinctoria is a species of flowering plant in the buckwheat family. Common names include Chinese indigo, Japanese indigo and dyer's knotweed. It is native to Southern China and Vietnam, and has been introduced to other parts of China, as well as Germany, Japan, Korea, Tibet, North and South Caucasus, parts of the Russian Far-East, and Ukraine.
The leaves are a source of indigo dye. It was already in use in the Western Zhou period (c. 1045 BC – 771 BC), and was the most important blue dye in East Asia until the arrival of Indigofera from the south.
Amphibious Bistort · Pink Headed Knotweed · Chinese Knotweed · Water pepper · Curlytop knotweed · Redshank · Persicaria microcephala · Small water-pepper · Vietnamese Coriander · Pinkweed · Asiatic Tearthumb · Dotted Smartweed
Text excerpted from the Wikipedia article Persicaria tinctoria 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.
