Karanj or Millettia pinnata is well-adapted to arid zones and has many traditional uses. It is often used for landscaping purposes as a
windbreak or for
shade due to the large canopy and showy fragrant flowers. The flowers are used by gardeners as
compost for plants requiring rich nutrients. The bark can be used to make twine or rope and it also yields a black gum that has historically been used to
treat wounds caused by poisonous fish. The wood is said to be beautifully grained but splits easily when sawn thus relegating it to firewood, posts, and tool handles.
The Indian Nursery grows this plant in millions throuhout the year.
While the oil and residue of the plant are toxic and will induce nausea and vomiting if ingested, the fruits and sprouts, along with the seeds, are used in many traditional remedies. Juices from the plant, as well as the oil, are
antiseptic and resistant to pests. In addition M. pinnata has the rare property of producing seeds of 25–40% lipid content of which nearly half is oleic acid. Oil made from the seeds, known as pongamia oil, is an important asset of this tree and has been used as
lamp oil, in soap making, and as a
lubricant for thousands of years. The oil has a high content of triglycerides, and its disagreeable taste and odor are due to bitter flavonoid constituents including karanjin, pongamol, tannin and karanjachromene. It can be grown in rain water harvesting pits /ponds / lands up to
6 meters water depth without losing the
greenery and to produce
bio diesel.
Dense network of lateral roots of Karanj makes this tree ideal for controlling
soil erosion and binding sand dunes.