Pongamia Pinnata is a leguminous plant that produces an oilseed. It is native to the Indian subcontinent, China, Japan, Malaysia, Australia and Pacific Islands. It belongs to the pea family, Fabaceae. The plant is used as a source for bio-diesel for its oilseeds.
Karanj is a pretty low maintenance tree and relatively easy to care for.
It can be grown in full sun or partial shade.
The leaves start out as soft burgundy coloured and as the season progresses they mature to glossy deep green. Small clusters of purple, pink and white flowers blossom on the tree throughout the year creating a beautiful contrast of colour in the green background. The flowers mature to brownish seed pods. The growing season starts in spring.
The plants have elaborate root systems and are very drought resistant. They do not require frequent watering. Water it deeply during the summers. Check the topsoil before watering the tree again.
The plant does fairly good on most soils from sandy, stony to clayey. They can resist saline soils better than most agricultural plants of India. PH of the soil shouldn't be above 7.5 however, as that may lead to nutritional deficiencies in the plant.
It can grow up to 15 to 25 m in height and spreads wide to form a large canopy. They do not require regular pruning but you can prune them to give appropriate shapes.
Fertilizing will lead to better fruit and seed production. Fertilize with an N-P-K fertilizer during the growing season i.e. from March to May or June. Water the plant before fertilizing to prevent fertilizer burn. Try to use organic fertilizers.
The plant usually remains free from pests and diseases but sometimes caterpillars, aphids and mealybugs might cause defoliation. Spray them off with water. If the problem continues, treat with appropriate insecticides.
Karanj is often planted as an ornamental and shade tree. It can be planted alongside highways and canals to stop soil erosion. The flowers are used in the preparation of rich compost. Wood is used as firewood. Oil made from the seeds also known as Honge oil is used as fuel and lubricant. It is an important source of biodiesel.