Pittosporum tenuifolium is a small evergreen tree endemic to New Zealand – growing up to 10 m (33 ft) – commonly known as kōhūhū and black matipo, and by other Māori names kohukohu and tawhiwhi.

The trunk is slender (30–40 cm diameter) with a mottled dark grey bark color[3] that progressively turns black towards the tips of the branches[4] The leaf coverage is compact in kōhūhū; the leaves are arranged alternately on the stem[3] and the petiole is short.

[6] The fruit is covered in a small layer of hairs during early maturation that is progressively discarded as the capsule ripens.

[3] It grows readily in forested areas that have been disturbed[4] or in reverting farmland, playing an important role in ecological succession.

[3] In horticultural production, the sticky substance coating the seeds is removed before sowing, as it acts as a germination inhibitor.

[13] Flowering happens in late spring, from October to November, and the maturation of the fruit happens between mid-summer and autumn, from January to March.

[15] Planting it in damp conditions can cause winter leaf drop,[15] which likely explains why kōhūhū is not found growing on the West Coast of New Zealand.

In its role in ecological succession, kōhūhū is often found at an earlier stage than its relative lemonwood (another endemic Pittosporum), and usually inhabits less fertile soils.

[3] There are over 50 insect species listed in the Plant-SyNZ database[16] that either feed on or parasitise kōhūhū, including wasps, sucking bugs, flies, moths, butterflies, thrips, mites and beetles.

As soon as the weevil's larvae hatch, they start feeding on the stamens and ovaries of the flowers, switching to the leaves once they reach adulthood.

Cottony cushion scale (Icerya purchasi),[20] an Australian bug, soft wax scale (Ceroplastes destructor), an import from overseas[21] and the Australian green shield bug (Glaucias amyoti), native to New Zealand despite its name[22] also parasitise the Pittosporum species, but have a more varied range of hosts.

[23] Pythium irregulare has been recorded as a pathogen of kōhūhū, causing foliar blight, rot, and eventually death.

Several hybrids and cultivars have been developed[3] and five varieties won the Royal Horticultural Society's Award of Garden Merit due to their ability to cope in the growing conditions of the United Kingdom:[26] Kōhūhū has the potential to be used as the host of the threatened root parasite plant wood rose (Dactylanthus taylorii).

[36] The crushed bark has been soaked in water and the resulting mixture used to treat breast or chest ailments, and the remaining liquid taken orally.