¶ Indigofera tinctoria
Indigofera tinctoria, also called "True Indigo", is a spcies of plant from the Fabaceae family. It is a plant with a number of growth habits, but in its native range it grows as a small perennial shrub 1-2 meters. It has been utilized for thousands of years as one of the primary sources for indigo dye.
Sidebar Elements:
Binomial name
Indigofera tinctoria
Common Name
True Indigo
Taxonomy
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fabales
Family: Fabaceae
Subfamily: Faboideae
Genus: Indigofera
Species: I. tinctoria
Native Range:
Southeast Asia, Malaysia to India
Extant Range:
Pan-tropical distribution
Conservation Status:
Least Concern
¶ Etymology
What is the origin of this species name(s)?
The "tinctoria" in the species binomial is commonly used in some variation for plants within a genus that are particularly known for their applications as a dye.
The name "true indigo" is often used to differentiate it from other species of indigo that may produce less of the desired dye (e.g. Japanese Indigo) or plants that look like I. tinctoria but do not produce any significant amount of the eponymous dark blue dye (e.g. False Indigo).
¶ Description
What is the physical description of this species?
True indigo is a shrub 1 -2 meters (3 ft f in - 6 ft 7 in) high. It may be an annual, biennial, or perennial, depending on the climate it is grown within.
It has light green pinnate leaves and sheafs of pink or violet flowers.
The rotenoids deguelin, dehydrodeguelin, rotenol, rotenone, tephrosin and sumatrol can be found in I. tinctoria[1]
¶ Reproduction
How does this species typically reproduce?
I. tinctoria typically reproduces by seed, especially in areas where the climate causes it to be grown as an annual plant.
¶ Habitat and Distribution
What is the habitat of this species? What is its native range? What is its extant range?
The habitat of I. tinctoria is variable within its range, but it universally favour locations that provide it with full sun, heat, and humid conditions.
Its long history of cultivation make its exact native range unknown but it currently ranges from West Africa to India. [2]
¶ Invasiveness Status
If this plant is known to demonstrate invasive behaviour, to what extent and in what regions?
This plants significant sentitivity to cold temperatures limits it ability to spread outside of its current pan-tropical distribution.
¶ Conservation Status
If this plant is subject to conservation efforts: where, why, and to what extent?
Due to its utilization as a major dye plant there is little risk of true indigo facing extinction in the forseeable future.
¶ Modern Ecological Niche
What niche does this species fill in modern ecology? How will climate change affect its range?
The species ecological niche is as a nitrogen fixer and as a shelter for small bird species when it is able to grow as a shrub. In areas where it only grows as an annual or biennial its ecological interactions are limited.
Its ecological niche is projected to change as a result of climate change and may expand in some areas where average temperatures rise while contracting in others where the average humidity drops or becomes too inconsistent.[3] [4]
¶ History
What is this species history?
This species has a significant and well documented history.
¶ Evolutionary History
What do we know about its evolutionary history?
The evolutionary history of I. tinctoria has proven challenging to map for taxonamists as the genus Indigofera has a relatively large number of species within it that are often identical in their morphology, overlap in their range, and widespread distribution.[5]
¶ Human History
What is the known historic relationship between this plant and humans?
¶ Historic Use
The most obvious historic application of Indigofera species was as a dye source as it is famous for producing a blue dye that is both relatively resistant to fading from UV exposure as well as capable of being applied to unmordanted fabric and fibres. The relative lack of other sources of blue colouring made indigo a critical cultural and economic product for thousands of years until the introduction of synthetic dyes in the 19th and 20th centuries. After this point its use as a dye source began to decline but it remains one of the most widely cultivated and utilized dye plants to this day due to it unique desirable qualities.
Beyond its use in colour it also has a history of medicinal usage, especially in some east asian cultures where it has been recorded being used for a variety of treatments.[link to plants for a future page]
Note: The section covering the medicinal applications of this plant requires additional work. You should not use any plant or fungus listed on this wiki for a medicinal application without consulting a medical expert first.
The plant has also been used traditionally as a cover crop in addition to its use as a cash crop due to its ability to fix nitrogen from the atmosphere. This is an ability that sets it apart from other commonly cultivated sources of indigo, such as Japanese Indigo or woad, which often deplete the soil their are grown in and require regular fertilization.
¶ The Silk Road
For some time it was believed by many Europeans that indigo originated from a mineral and not a plant, an idea that was reinforced by some of the traders that dealt in the dye in the middle east. This was also in part due to the fact that processed indigo was transported in compressed bricks, which would have set it apart from other commonly used dyes at the time. [wild color]
¶ Greater Spread to Europe
The plant became significantly more available in Europe after Vasco da Gama charted the sea route to the East Indies in 1498. This significantly increased its competition with locally produced woad as a source of blue colour for textiles and paints.
By the early 17th century indigo was the British East India Company's most valuable commodity.
¶ Competition with Woad
Prior to the introduction of tropical indigo into the European market the dominant source of blue in the region was from woad (Isatis tinctoria), which had become an increasingly important cash crop as of the middle ages. In the 13th century German and French merchants exported indigo derived from woad to surrounding countries such as Belgium, England, Hungary, Poland, and Italy.
Once the indigo produced from Indigofera plants began to flow into Europe this had serious implications for the domestic market and producers who sources their indigo from locally grown woad.
This led France to ban its import in 1598 to protect domestic producers who relied on less productive woad. This ban lasted to some degree until 1737. A number of German states are also known to have past similar protectionist measures in an attempt to protect their domestic industry.
¶ Connection to Slavery
In the Americas the high demand for indigofera plants as a cash crop contributed to planted importing more slaves. This placed indigo in the same catagory as sugarcane, rice, and cotton as an economic incentive for the horror of chattel slavery that was rife in the colonized Americas throughout the 16th to 19th centuries. The conditions of slaves on indigo plantations were considered especially horrific as the fermentation of the indigo attracted massive quantities of flies. The cultivation of indigo required approximately one worker per acre, which led slavers to import a large number of enslaved people for the task. By the 1600s indigo was the chief crop of Central America that was exported by the Spanish Empire.
Much of this cultivation occured in Central America, the Caribbean, and areas of Brazil.
The history of indigofera cultivation in North America dates back to around the 1720s when the French began plantations in Louisiana using seeds sourced from the Carribean. Previously North American cultivation was relegated to woad production in the north-east of the continent by the Dutch.
In the southern area of North America the plant was often companion planted with rice, which allowed slavers to work their enslaved people year-round.
The yield produced in the southern states was less than the yield achieved in Central America.
The end of slavery significantly lowered the production of indigo in North America, until it was completely abandoned at any significant scale after the introduction of synthetic dyes in the 20th century.
¶ Cultivation Details
¶ Propagation
What information do we have on how to propagate this species?
¶ Sexual Reproduction
What information do we have on how to propagate this species by seed or spore?
- Sow seeds in late spring [wild color]
¶ Asexual Reproduction
What information do we have on how to propagate this species by cutting or division?
¶ Growing Conditions
This plant prefers fertile soil that is well drained and positioned in full sun. Areas that are known to be significantly windy should be avoided.
¶ Common Pests and Diseases
Historically some of the primary pests that can ruin and indigo crop include locusts and certain catterpillars. In North America the latter is more of a concern as the former disappeared from the continent when the American Locust went extinct in the 20th century.
¶ Harvesting
Harvesting Time: Late summer to fall [wild colour]
¶ Modern Applications
What are the ways that this species is currently worked with?
¶ Emerging Applications
¶ Collective Programming
What programs or projects is this species currently relevant to?
¶ See Also
¶ References
Indigo - Encyclopedia of Cultivated Plants: From Acacia to Zinnia. (n.d.). Ebrary. https://ebrary.net/27957/environment/indigo
Shields, J. (2023, March 8). The Dark History of Indigo, Slavery's Other Cash Crop. HowStuffWorks. https://history.howstuffworks.com/world-history/indigo.htm#pt3
Splitstoser, J. C., Dillehay, T. D., Wouters, J., & Claro, A. (2016). Early pre-Hispanic use of indigo blue in Peru. Science Advances, 2(9). https://doi.org/10.1126/sciadv.1501623
Dean, J., & Casselman, K. D. (2010). Wild Color, Revised and updated edition: The Complete Guide to Making and Using Natural Dyes. National Geographic Books.
Boutrup, J., & Ellis, C. (2018). The art and science of natural dyes: Principles, Experiments, and Results.
Luhanko, D., & Neumüller, K. (2018). Indigo: Cultivate, dye, create. Pavilion.
Kamal R.; Mangla M. (1993). "In vivo and in vitro investigations on rotenoids from Indigofera tinctoria and their bioefficacy against the larvae of Anopheles stephensi and adults of Calmlosobruchus chinensis". Journal of Biosciences. 18 (1): 93–101. doi:10.1007/BF02703041 ↩︎
https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:500111-1 ↩︎
Mathur, M., & Mathur, P. (2024). Ecological niche modelling of Indigofera oblongifolia (Forssk.): a global machine learning assessment using climatic and non-climatic predictors. Discover Environment, 2(1). https://doi.org/10.1007/s44274-024-00029-1 ↩︎
Kapumha - NRM.pdf · Electronic Theses and Dissertations · EScholar. (n.d.). http://escholar.buse.ac.zw/s/etd/media/5450 ↩︎
Zhou, S., Wang, F., Yan, S., Zhu, Z., Gao, X., & Zhao, X. (2023). Phylogenomics and plastome evolution of Indigofera (Fabaceae). Frontiers in Plant Science, 14. https://doi.org/10.3389/fpls.2023.1186598 ↩︎