Castanospermum is native to the east coast of Australia in Queensland and New South Wales, and to Vanuatu and New Caledonia. Some common names of Castanospermum are: Black Bean, Bean Tree, Moreton Bay Chestnut andMoreton Bay Bean.

 

Castanospermum is a handsome, evergreen tree growing to 40 m tall. It has glossy dark green pinnate leaves and low spreading branches. During October - November, it bears sprays of red and yellow pea-shaped flowers 3-4 cm long, which are partly hidden by the dense foliage. Following flowering in March - May, large cylindrical pods measuring 12-20cm by 4-6 cm are produced. These pods split in two, revealing 3-5 large beans like seeds weighing about 30 grams. The nectar produced by the flowers attracts birds, bats and butterflies.

 

The trunk of Castanospermum is usually cylindrical, with notable flanges appearing with age. The bark is dark brown with transverse lighter brown lines and longitudinal lines of grey pustules, smooth or wrinkled leathery. The branches are light brown, young shoots downy, with numerous grey raised lenticels and prominent leaf scars.

 

Castanospermum grows in moist, fertile, well-drained soils on terraces on the side of mountains or along the banks of rivers and streams. It grows in a soil-based potting mix in full light, shaded from hot sun, in moderate humidity. Castanospermum prefers a medium level of filtered sunlight. The soil should be kept moist at all times. The plant tolerates only light frost. It has moderate water needs and is quite drought resistant.

 

The seeds are poisonous, but become edible when carefully prepared by pounding into flour, leaching with water, and roasting. The timber, which somewhat resembles walnut, is soft, fine-grained, and takes a good polish, but is not durable

 

Did you know?

 

·        Castanospermum australe (Moreton Bay Chestnut or Blackbean), is the only species in the genus Castanospermum.

·        Castanospermum name derives from Greek ‘castanon’ the Chestnut tree and sperma a seed, referring to the similarity in appearance of the seed.