Shrub

Kohuhu

Pittosporum tenuifolium · Pittosporaceae · also called pittosporum, black matipo
By Hannah Price · Updated

Kohuhu seasonal calendar
JanFebMarAprMayJunJulAugSepOctNovDec
FlowersFlowers in May
PlantPlant in AprilPlant in MayPlant in September
PrunePrune in AprilPrune in July
Looks goodLooks good in JanuaryLooks good in FebruaryLooks good in MarchLooks good in AprilLooks good in MayLooks good in JuneLooks good in JulyLooks good in AugustLooks good in SeptemberLooks good in OctoberLooks good in NovemberLooks good in December

Overview

This New Zealand shrub is grown mainly for its foliage: small, glossy, wavy-edged leaves held on dark stems, prized by florists. Tiny chocolate-purple flowers in late spring are easy to miss, but their honey scent in the evening is a treat. Choose 'Tom Thumb' for purple leaves, 'Golf Ball' for a naturally round dwarf, 'Silver Queen' or 'Irene Paterson' for silvery-white variegation, and 'Warnham Gold' for golden tones.

Where to grow kohuhu

It shines in seaside gardens, tolerating salt spray and wind, and makes a dense, fast hedge in the south and west. Inland and further north it needs a sheltered spot with good drainage, as hard frosts combined with cold wind can kill it. Dwarf forms suit pots and modern planting schemes.

Planting

Plant in spring so the roots establish before winter, or in early autumn in mild districts. Avoid waterlogged ground and add grit to heavy clay. For hedging, space plants roughly 50–60 cm apart.

Care through the year

Spring

Check for frost damage and feed with a general fertiliser once growth resumes.

Summer

Water newly planted shrubs and containers in dry periods and clip hedges in midsummer.

Autumn

Stop feeding so the soft growth can ripen before the colder months.

Winter

Wrap young or potted plants in fleece in freezing, windy weather and keep pots off saturated ground.

Pruning

Shape plants in spring, after frosts have passed, and give hedges a second trim in July. It tolerates regular clipping into topiary shapes. Cut back any frosted shoots to healthy green wood in late spring once you can see what has survived.

Propagation

Semi-ripe cuttings in late summer root with gentle bottom heat; expect lower success than with easier shrubs, so take several. Seed from the species germinates, though variegated varieties will not come true.

Common problems

Cold winds and severe frost are the biggest threat, causing scorched or blackened foliage. Pittosporum psyllid, a sap-sucking insect, can distort young leaves; clip out affected shoots. Soft scale and sooty mould occasionally appear on stressed plants.

Guides to the problems most likely to affect kohuhu:

Something else wrong? Diagnose it by symptom.

Month-by-month reminders

Jobs for this plant come round in April, May, July and September. Each month page lists everything else worth doing in the garden at the same time.

Related plants

Sources

Botanical names follow Kew's Plants of the World Online; growing attributes were checked against the references below. Text is our own. See our editorial policy.