Indigofera tinctoria (True Indigo) is a small flowering shrub that is the original source of purple dye. True Indigo has evergreen leaves and produces beautiful pink/purple flowers during Spring. The plant is easy to grow, don’t need much water and attracts bees into the garden. Like most plants in the Pea family, they also help by improving the soil for other plants nearby.
Suitable for Cold, Temperate, Dry, Mediterranean, Sub-Tropical and Tropical climates.
For a native variety, check out our page on the Australian Indigo.
Growth
Indigofera tinctoria is an evergreen flowering native that reaches heights of up to 2 metres (7 feet). True Indigo has an upright growth habit and light green leaves. It grows in poor soils and prefers warm temperate or humid conditions.
Pinnate shaped leaves stretch 50mm long and are the source of the blue dye that was highly sought after up until the early 20th century.
As part of the legume family, it helps nearby plants in the garden by increasing the nitrogen levels in the soil and atmosphere. And as an additional bonus, their attractive pink or purple flowers bring lots of beneficial insects into the garden.
Fruits follow soon after with small, thin pods that contain up to 10 seeds each that have matured once the pod becomes a reddish-brown.
In warmer climates, the plant is a perennial and lives for between 2-4 years. In colder climates that regularly dip below 10°C / 50°F, True Indigo dies off and is considered an annual. Even so, it is commonly grown as an annual in crop rotations to help improve the soil while providing forage for livestock.
FAMILY:
Fabaceae
CLIMATE:
Temperate, Dry, Sub-Tropical and Tropical.
TEMPERATURE RANGE:
10°C to 30°C / 50 to 86°F
SOIL TYPE:
Most soil types are ok.
LOCATION:
Full Sun
HEIGHT:
Up to 2 metres (7 feet)
WIDTH:
Up to 2 metres (7 feet)
pH:
6.0-7.5
GROWTH TYPE:
Perennial or Annual Evergreen.
WATER REQUIREMENTS:
Low
POLLINATION:
Pollinated by bees and wasps.
MATURITY:
4-6 months
GERMINATION RATES:
75-95%
GERMINATION TIME:
2-3 weeks
SEEDS PER GRAM:
Approximately 150
MEDICINAL QUALITIES:
Yes.
WEED POTENTIAL:
Yes
EDIBLE:
No
SEED STORAGE & VIABILITY:
Cold Storage at 4°C (Fridge) up to 3 years.
FACTS ABOUT INDIGOFERA TINCTORIA (True Indigo)
The explorer Marco Polo of the thirteenth century was the first European to write about the Indigo from India. Throughout the Middle Ages, Indigo was popular in Europe as a dye used for easel painting.
To obtain the dye, the plants leaves are soaked in water and then fermented to convert the indican into the blue dye indigotin.
The native location of True Indigo has never been entirely clear. Some suggest that the Malaysian Peninsula is the original source. However, humans have spread the seeds and plant for over 6000 years so any suggestion of a native region is guesswork.
From the 1700s, Indigo became a prominent cash crop in the southern states of the USA. That was before commercial synthetic indigo replaced natural dyes in 1897. By 1914, 96% of the world’s Indigo dye was produced synthetically.
Under England’s reign of Queen Elizabeth and the Saxony by the Elector, True Indigo was prohibited. The later described it as “a corrosive substance, and food fit only for the devil”.
