noun
dyer's knotweed; Persicaria tinctoria
A plant used to produce indigo dye. The name is usually written in katakana.
See also: 藍
アイタデは藍染めの原料として栽培される。
Dyer's knotweed is cultivated as a raw material for indigo dyeing.
藍 refers to indigo dye or the indigo plant in general, while アイタデ specifically refers to Persicaria tinctoria, a plant used to produce indigo.
The name likely derives from 藍 (あい, indigo) and 蓼 (たで, knotweed), referring to its use in indigo production. The exact historical derivation is uncertain.