(Persicaria tinctoria / Japanese Indigo)
Dye Colour: Blue (Indigo) | Produced in Ireland
Persicaria tinctoria, commonly known as Japanese Indigo, is a fast-growing annual prized by natural dyers for its high indigo content and reliability in temperate climates. Its vibrant green leaves are the source of rich blue indigo pigment, suitable for fresh-leaf dyeing, pigment extraction, and traditional Sukumo vats.
A cornerstone plant for natural dye gardens, Persicaria produces clear, vibrant blues when grown well and harvested at the right moment. It is very frost sensitive and should be protected with horticultural fleece if late frosts occur after planting out.
Dye Fastness: Excellent (with proper indigo processes)
Sowing period:
Indoor sowing mid-March to mid-April
Direct sow outdoors from mid-May, once frost risk has passed
Germination time: 7–14 days
Height: 60–90 cm (24–36 in)
Preferred location:
Full sun to light shade; fertile, consistently moist but well-drained soil
Climate note:
Frost and wind sensitive — sheltered planting improves growth and pigment yield
Harvest leaves when plants reach 40–50 cm, up to 2–4 times during the growing season, allowing fresh regrowth between cuts. For fresh-leaf dyeing or pigment extraction, leaves should be processed as soon as possible after harvesting to retain colour strength.
This is a white-flowered variety that produced the highest pigment yield in our 2024 Persicaria variety trials, which compared seven different types grown in Ireland. It was also the earliest flowering variety, making it particularly suitable for outdoor seed saving in Ireland in most years.
(See the final product image for trial results — this variety is shown as Sample No. 5.)
Open-pollinated & organically grown in Ireland
Germination rate: 85%
Irish seed licence: IE010713
Approx. 25 seeds per packet
Please note: Seeds and plants can only be shipped within Europe.
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