Common Name: Tawhiwhi

General Information

Pittosporum tenuifolium is an evergreen tree with a slender crown; it can grow up to 10 metres tall. The bole can be up to 30cm in diameter, occasionally more[, , ].
The planIt is harvested from the wild for local use as a food and source of materials. It is often grown as an ornamental, where it can be used to make a hedge, and the cut foliage is much used in floristry[].

Known Hazards

This plant contains saponins[, ].
Although poisonous, saponins also have a range of medicinal applications and many saponin-rich plants are used in herbalism (particularly as emetics, expectorants and febrifuges) or as sources of raw materials for the pharmaceutical industry. Saponins are also found in a number of common foods, such as many beans.
Saponins have a quite bitter flavour and are in general poorly absorbed by the human body, so most pass through without harm. They can be removed by carefully leaching in running water. Thorough cooking, and perhaps changing the cooking water once, will also normally remove most of them. However, it is not advisable to eat large quantities of raw foods that contain saponins.
Saponins are much more toxic to many cold-blooded 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 and make them easy to catch[].

Botanical References

, ,

Range

New Zealand - North and South Islands.

Habitat

Coastal to lower montane forests, North and South Islands, especially from North Cape and southwards[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	7.00 m
Growth Rate	Medium
Pollinators	Insects
Cultivation Status	Ornamental, Wild

Cultivation Details

Pittosporum tenuifolium is hardy to about -10°c[], it is tender outside the milder areas of Britain, but often self-sows when happy. Plants have reached a height of 9 metres in a sheltered position in eastern England[].
Succeeds in most well-drained soils of reasonably good quality in full sun or light shade[, ]. Succeeds in dry soils. Fairly tolerant of maritime exposure[, ], but it can be killed by cold winds[].
A very ornamental plant[], there are many named varieties[].
Very amenable to pruning, plants can be cut right back into old wood if required[].
Although flowers usually appear to be hermaphrodite, many species of Pittosporum are functionally dioecious, with individual specimens bearing mainly or totally flowers of one sex only. Even so, occasional functionally hermaphrodite flowers will appear and, in at least some species, these flowers can be self-compatible and produce fertile seed even in the absence of any other plants of that species[].
The species in this genus are also 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 are widely cultivated for their foliage which lasts a long time in water and is used in flower arranging[, ]. The flowers are honey-scented, the aroma being strongest in the evening[, ].
Plants in this genus are notably resistant to honey fungus[].

Edible Uses

A fragrant gum is obtained by bruising the bark or by incision. It is used as a masitcatory[, , ].

Medicinal

A gum-resin obtained from the trunk is of potential use in medicine[].

Agroforestry Uses:

Very tolerant of trimming, plants can be grown as a formal or informal hedge in exposed maritime areas, though they do not stand extreme exposure[, , ]. When grown as a formal hedge it is best trimmed in spring, though this will mean that the plant will not produce many flowers[]. A compromise is to only trim the hedge every other year[].

Other Uses

A fragrant gum obtained from the stem is used to scent oils[].

An essential oil rich in alpha-pinene is obtained from the stem[].

Propagation

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, mid summer in a frame. Poor to fair percentage[].
Basal ripewood cuttings late autumn in a cold frame[].