Herb: Karo

Latin name: Pittosporum crassifolium

Family: Pittosporaceae

Description of the plant:


5 m
(16 feet)



Habitat of Karo:

Forest margins and by streams on North and Kermadec Islands.

Other uses of the herb:

A dark blue dye is obtained from the seeds. The plant is a potential source of saponins. Saponins can be used to as a soap and, because of their bitter taste, they also have potential as a bird deterrent by spraying them over the plants. The bitterness can be easily removed by washing (or by the next rainfall!). Very tolerant of pruning and maritime exposure, this plant can be grown as a protective hedge by the coast in mild maritime areas. The plant has an extensive root system and can be used for binding sandy soils, dunes etc. Wood - very tough. Used for inlay.

Propagation of Karo:

Seed - sow when ripe in the autumn or in late winter in a warm greenhouse. The seed usually germinates freely. Prick out the seedlings into individual pots when they are large enough to handle, move the plants to a cold frame as soon as they are established and plant out late in the following spring. Consider giving them some protection from the cold during their first winter outdoors. Cuttings of half-ripe wood, 5 - 7cm with a heel, July/August in a frame. Poor to fair percentage. Basal ripewood cuttings late autumn in a cold frame.

Cultivation of the herb:

Forest margins and by streams on North and Kermadec Islands.

Medicinal use of Karo:

None known

Known hazards of Pittosporum crassifolium:

This plant contains saponins. Saponins are found in many foods, such as some beans, and although they are fairly toxic to people they are poorly absorbed by the body and most pass straight through without any problem. They are also broken down if the food is thoroughly cooked for a long time. Saponins are much more toxic to some creatures, such as fish, and hunting tribes have traditionally put large quantities of them in streams, lakes etc in order to stupefy or kill the fish.

Plant information taken from the Plants For A Future.