Bengal Indigo, Java indigo, Natal indigo
Indigofera arrecta
Family: Fabaceae
What it is like
Indigofera arrecta, commonly known as Bengal Indigo, Indigo, Natal Indigo, or Java Indigo, is a tropical small shrub of herb growing up to 4 m in height with partly woody stems and slightly hairy leaves. It has pink or brown flowers. It can be found in Africa. The leaves are used in the treatment of epilepsy, nervous disorders, diabetes, peptic ulcers, sores, gum infections, snake bites, gonorrhea, and jaundice. The leaves and roots are used externally to treat itching. The fruits and seeds are used to treat ophthalmia. Young leaves are cooked and eaten as a vegetable. Bengal indigo is also used as a cover crop and green manure. It is a major source of the blue dye 'indigo'. The twigs are used for cleaning teeth. Propagation methods are seed sowing and cuttings.
Indigofera arrecta is a PERENNIAL growing to 2 m (6ft) by 2 m (6ft) at a medium rate. See above for USDA hardiness. It is hardy to UK zone 10. It can fix Nitrogen. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid and neutral soils and can grow in very acid soils. It cannot grow in the shade. It prefers moist soil.
Height (m): 2
Where it is found
Deciduous and evergreen bushland; mixed woodland areas of cultivation and secondary growth; forest margins; (Hyparrhenia) grassland; roadsides; flood plains; pans; termitaria; waste ground; at elevations of 200 - 2,700 metres.
Tropical Africa - widely distributed throughout the continent from Senegal to Somalia, south to S. Africa. Also extending into Arabia.
Conservation Status: This taxon has not yet been assessed
Countries/locations it is found in
Africa, Asia, East Africa, Ethiopia, Guinea, Guinée, Guinea-Bissau, India, Indochina, Indonesia, Laos, Pan tropical, SE Asia, Senegal, Southern Africa, Vietnam, West Africa, Zambia, Zimbabwe,
How it is used
Food
Rating: 2
Young leaves - cooked and eaten as a vegetable. The root may be edible.
Root: includes bulbs, corms, tubers, rhizomes etc.
Medicine
Rating: 2
The leaves are used in traditional medicines for treating epilepsy and nervous disorders. An aqueous extract of the leaves from immature shoots is administered orally to patients with diabetes mellitus. A medicine for the management of peptic ulcer and methods of its preparation and use have been patented. The leaves are applied externally to heal sores and ulcers. An infusion or decoction of the leaves and roots is abortifacient, antispasmodic, diuretic, febrifuge, purgative, sedative, stomachic and vermifuge. It is used to treat conditions such as gum infections, snakebites, gonorrhoea, epilepsy and jaundice. The leaves and roots are used externally to treat itching. The fruits and seeds are used to treat ophthalmia. In several regions in Africa it is believed that the indigo dye in clothes prevents skin complaints
Abortifacient: Causes an abortion.
Antispasmodic: Relaxes muscular spasms and cramps, calming nervous irritation.
Diuretic: Acts on the kidneys, promoting the flow of urine.
Epilepsy: Used in the treatment of Epilepsy - a disorder in which nerve cell activity in the brain is disturbed, causing seizures.
Febrifuge: Reduces fevers.
Ophthalmic: Treats eye complaints.
Purgative: A drastic laxative causing a cleansing or watery evacuation of the bowels, usually with a griping pain.
Sedative: Gently calms, reducing nervousness, distress and irritation.
Skin: Plants used in miscellaneous treatments for the skin.
Stomachic: Aids and improves the action of the stomach.
Vermifuge: Expels and kills internal parasites.
Other
Rating: 4
Agroforestry Uses: The plant has potential as a cover-crop and green manure, especially in tea, coffee and rubber plantations. It gives shade and protection, suppresses weeds and improves the soil. The residue remaining after indigo extraction is also applied as manure. Other Uses: The plant is a major source of the blue dye 'indigo'. The leaves and twigs do not actually contain indigo but colourless precursors that must be extracted and then processed in order to produce the indigo dye. The harvested leafy branches are placed in a tank containing water to which some lime has been added, and are weighted down with planks. After some hours of fermentation, during which enzymic hydrolysis leads to the formation of indoxyl, the liquid is drained off and then stirred continuously for several hours to stimulate oxidation of the indoxyl. Afterwards the solution is left to rest and the insoluble indigo settles to the bottom as a bluish sludge. The water is drained and after the indigo has dried, it is cut into cubes or made into balls. To dye textiles, indigo is reduced to a soluble form by a fermentation process under alkaline conditions. In traditional preparations of the dye, various reducing agents such as molasses are used, together with coconut-milk, bananas and the leaves of Psidium guajava. The alkalinity is maintained by adding lime. After the textile has been dipped into solution it turns blue when exposed to the air. The twigs are used for cleaning teeth.
Compost: Plants used for activating compost heaps, providing biomass for composting, using as instant compost etc.
Dye: Plants that provide dyes.
Green manure: Fast-growing plants that can be used to increase the fertility of the soil.
Mulch: Used for covering the ground to conserve the nutrients in the soil.
Soil conditioner: Plants grown to improve the structure of the soil. See also Green manures.
Teeth: Plants used to clean and care for the teeth.
Food Forest: Plants for Edible Forest Gardens and Food Forests.
Nitrogen Fixer: Plants that fix nitrogen in the soil
How it is grown
A plant of the moist tropics, where it is found at elevations from 300 - 2,700 metres. It grows best in areas where annual daytime temperatures are within the range 22 - 30c, but can tolerate 16 - 36c. It can be killed by temperatures of c or lower. It prefers a mean annual rainfall in the range 1,700 - 2,200mm, but tolerates 400 - 4,300mm. Prefers a hot, moist climate and a position in full sun. Succeeds in a range of soils. Prefers a pH in the range 5 - 6, tolerating 4.5 - 6.5. Plants can tolerate up to two months of waterlogging. Plants can commence flowering 3 months after sowing the seed. Branches are harvested, usually early in the morning, when the plants are 4 - 5 months old and the crop has made a closed stand. This is usually also the flowering stage. About 3 - 4 months later the plants can be cut again; a crop can be harvested three times a year. The total life span for dye crops is 2 - 3 years, whilst for cover crops it is 1.5 - 2 years. Indigo is harvested only once when grown on paddy soils because the plants must give way for the next rice crop. The yield of this species is higher than from any other species of Indigofera. Annuals yields of 22 - 100 tonnes green matter per ha have been reported in India; the recorded output of indigo cake is 137 - 325 kg/ha per year. Natural hybridizations between I. Arrecta and I. Tinctoria do occur and especially in W Africa plants are often difficult to be assigned to one of the two taxa. This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby.
Propagating it: Seed - it possess a hard seed-coat and must be scarified. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them!) and then soaking them for 12 - 24 hours in warm water. By this time they should have imbibed moisture and swollen - if they have not, then carefully make a nick in the seedcoat (being careful not to damage the embryo) and soak for a further 12 hours before sowing. Sowing is done either on seed-beds or directly into the field, 3 - 4 seeds per hole, 60 cm apart within rows and 45 - 60 cm between rows. Germination takes about 4 days. When seed-beds are used, seedlings are transplanted at 4 - 6 weeks. Cuttings are made by dividing well-developed branches into pieces 30 cm long, which are kept for 2 - 3 days in a cool place before planting. Cuttings, 2-3 per hole, start rooting by the second week.
Best place to grow:
Habit: Perennial
Hardiness: 10-12
Growth: Medium
Soil: Light (sandy), medium, heavy (clay)
Shade: No shade
Moisture: Moist
Things to keep in mind
Its other names
Local names
Bengal indigo, Java indigo, Natal indigo, Natalindigo - German, añil de Java - Spanish. Baludo, Banhepe, Bno, Caro, Carodim-o, Caromessem-o, Carre, El badaba, Gara, Garatchendo, anileira de java, añil de java, baba, baba tamau, bengal indigo, java indigo, lademadui, natal indigo, natal indigo leaf, natalindigo, umusororo,
Synonyms
Indigofera kisantuensis De Wild. & T.Durand Indigofera scopa De Wild. & T.Durand Indigofera tinctori