Karo, Stiffleaf cheesewood
Pittosporum crassifolium
Family: Pittosporaceae
What it is like
Pittosporum crassifolium is an evergreen Shrub growing to 5 m (16ft) by 3 m (9ft). See above for USDA hardiness. It is hardy to UK zone 9. It is in leaf all year, in flower in May. The species is monoecious (individual flowers are either male or female, but both sexes can be found on the same plant). The plant is self-fertile. Suitable for: light (sandy) and medium (loamy) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers dry or moist soil. The plant can tolerate maritime exposure.
Height (m): 5
Where it is found
Forest margins and by streams on North and Kermadec Islands.
New Zealand. Naturalized in Britain in the Scilly Isles.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 0
Medicine
Rating: 0
Other
Rating: 3
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.
Dye: Plants that provide dyes.
Hedge: Plants that can be grown as hedges.
Soap: Plants used directly as a soap substitute.
Soil stabilization: Plants that can be grown in places such as sand dunes in order to prevent erosion by wind, water or other agents.
Wood: A list of the trees and shrubs that are noted for having useful wood.
Hedge: Hedge
Scented Plants: Plants noted for their scent
How it is grown
Succeeds in any well-drained soil, including dry soils, preferably in a sunny position but also succeeding in light shade. Plants are very resistant to maritime exposure. This species is not very cold-hardy in Britain, succeeding outdoors only in the milder areas of the country. Plants grow very well on the Scilly Isles but have not been proved on the mainland.Other reports say that it grows well in south-western England. Very amenable to pruning, plants can be cut right back into old wood if required. The flowers are sweetly scented, they are borne in terminal clusters of either up to 10 males or up to 5 females. Plants only flower freely in mild areas of the country. The species in this genus are very likely to hybridize with other members of the genus. When growing a species from seed it is important to ensure that the seed either comes from a known wild source, or from isolated specimens in cultivation. Plants in this genus are notably resistant to honey fungus.
Propagating it: 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.
Best place to grow: Woodland Garden Sunny Edge; Dappled Shade; Hedge;
Habit: Shrub
Hardiness: 8-11
Growth:
Soil: Light (sandy), medium
Shade: Semi-shade, no shade
Moisture: Dry, moist
Things to keep in mind
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.