Slender Kōhūhū

Pittosporum pimeleoides

At Risk - Naturally Uncommon

Pittosporum pimeleoides , commonly known as Slender Kōhūhū, is a rare and exceptionally graceful native shrub endemic to the northern regions of New Zealand. Unlike the more common, robust members of the Pittosporum genus, the Slender Kōhūhū is defined by its delicate, wiry habit and very narrow leaves that are often arranged in elegant whorls. A specialist of Northland's coastal woodlands and kauri forests, it is a plant of great refinement and subtle beauty. Classified as "At Risk - Naturally Uncommon," it is a prized find for botanical enthusiasts and a sophisticated addition to native gardens that aim to protect our threatened Northland flora. Its small, night-scented flowers, which bloom primarily in winter, add a layer of sensory delight to the garden when many other plants are dormant.

Close-up of the small yellow and red striped flowers of Pittosporum pimeleoides — Image credit: Slender Kōhūhū (*Pittosporum pimeleoides*) - photo by Wikipedia

Plant Description

Slender Kōhūhū is a much-branched evergreen shrub that typically grows between 0.6 and 2.5 meters in height. It has an open, wiry growth habit, with slender branches that are initially covered in a fine greyish-white or brownish hair (tomentum), becoming smooth and dark with age.

The leaves are a highlight of the species: they are small and narrow, measuring up to 2.5 cm long, and are typically arranged in whorls or clusters along the branchlets. The colour can range from a soft pale green to a deeper red-green, depending on the plant's exposure to light. In winter, it produces small terminal clusters of dainty flowers. These are typically yellow with a distinct central red stripe on each petal, although entirely yellow or cream forms exist. These flowers are highly fragrant, especially at night. The fruit is a small, pointed woody capsule, 6-12 mm long, which splits into two valves to reveal sticky black seeds embedded in an orange pith.

Quick Facts

Plant Specifications

*Pittosporum pimeleoides* quick facts
Scientific Name	Pittosporum pimeleoides
Family	Pittosporaceae
Height	0.6-2.5 metres
Growth Form	Graceful, wiry, much-branched shrub
Foliage	Small, narrow leaves in elegant whorls
Flowers	Yellow with red stripes; Night-scented; Winter
Light	Partial shade to full sun (prefers filtered light)
Soil	Free-draining, loamy or gritty
Hardiness	Hardy to light frost; prefers humidity
Water Needs	Moderate; requires consistent moisture while establishing
Spread	0.8-1.5 metres
Frost Tolerance	Moderate
Salt Tolerance	Moderate
Growth Rate	Slow to Medium
Lifespan	Perennial

Climate Best Suited to

Slender Kōhūhū is a plant of the warm-temperate North. It thrives in the mild, humid climates of Northland and the Auckland region. It is perfectly adapted to the coastal forests and kauri-associated ecosystems of the upper North Island. While it can handle light winter frosts once established, it is not suited to the severe continental climates of the inland South Island. It requires a site that maintains reasonable air humidity.

Regional Suitability

City suitability for Slender Kōhūhū
City	Climate Suitability
Whangārei	Ideal (Native Habitat)
Auckland	Ideal
Hamilton	Ideal
Rotorua	Suitable (sheltered site)
Tauranga	Ideal
Gisborne	Suitable
New Plymouth	Suitable
Whanganui	Suitable
Palmerston North	Suitable
Napier	Suitable (needs moisture)
Wellington	Suitable (sheltered from wind)
Nelson	Suitable (warm, sheltered site)
Christchurch	Marginal (requires protection)
Dunedin	Not Recommended
Invercargill	Not Recommended

Plant Habitat

Naturally, Pittosporum pimeleoides is a specialist of the northern forest floor and edges. Its range is centred in Northland, with notable populations around the Bay of Islands. Its primary habitats include coastal woodlands, open kauri ( Agathis australis ) forest, and secondary regrowth shrublands. It thrives along ridgelines and in other well-drained, often nutrient-poor sites such as gumlands. It is a colonizer of light gaps caused by disturbances like fires or slips. Occasionally, it can be found in riparian vegetation where it tolerates seasonal flooding, though it always requires a free-draining substrate.

Plant Conservation

Slender Kōhūhū is currently classified as "At Risk - Naturally Uncommon." While it is not in immediate danger of extinction, its naturally restricted range and specialized habitat make it vulnerable to localized threats. The primary pressures come from habitat loss due to land development and the invasion of Northland's forests by aggressive exotic weeds. Browsing by introduced mammals like possums and rats (who consume the seeds) also hinders regeneration. Conservation efforts focus on protecting known forest remnants and promoting the species in native restoration projects within Northland.

Growing Requirements

Soil Requirements

Requires excellent drainage. It thrives in light, loamy or gritty soils and is perfectly at home in the poor, acidic soils typical of kauri or gumland environments.

Well-drained loam or sand
Tolerates low soil fertility
Avoid heavy, waterlogged clay

Light Requirements

Performs best in partial or dappled shade, mimicking its natural forest-understory position. It can tolerate full sun if the roots are kept cool and moist, but it may become more stressed in high-heat areas.

Filtered or dappled light
Partial to full shade
Shelter from intense direct sun

Water Requirements

Requires consistent moisture to establish its root system. Once mature, it is remarkably drought-tolerant, but it appreciates regular watering during dry summer months to maintain its lush appearance.

Moderate watering when young
Appreciates humidity
Dislikes dry root zones

Planting Guide

Best Planting Practices

Plant in autumn or spring. Choose a sheltered, shaded spot with good air movement but protection from cold winds. Dig a hole significantly larger than the root ball and enrich the soil with plenty of organic matter like leaf mould, bark, or compost. If your soil is heavy, incorporate extra sand or grit to improve drainage. Plant at the same depth as the nursery container. Water in thoroughly and apply a deep layer of organic mulch to keep the roots cool and the soil moist. This species is slow-growing, so ensure it is not smothered by faster-growing neighbors while it establishes.

Ecological Role

Environmental Benefits

Slender Kōhūhū is an important part of the forest's vertical biodiversity. Its fragrant winter flowers provide a valuable nectar source for native moths and other night-flying insects when few other sources are available. The black seeds are attractive to native birds, who are key to its dispersal. Its open, wiry habit provides a unique texture within the forest understory, offering refuge for small invertebrates.

Uses & Significance

Garden Uses

A sophisticated and unique choice for northern native gardens:

Elegant feature in shaded native borders
Excellent for large containers or pots
Unique architectural form for courtyard gardens
Perfect for creating a lush, Northland forest aesthetic

Ecological Value

Supports specialized northern forest pollinators and birds.

Cultural Significance

Traditional Uses and Values

The name Kōhūhū connects this plant to the wider family of Pittosporums, which were highly valued by Māori for their aromatic resins and medicinal properties. As an endemic treasure of the Northland region, this species is part of the unique botanical identity of the northern ngāhere (forest). It represents the delicate and diverse vertical layers of the traditional forest landscape.

Landscaping Uses

Garden Design Applications

In landscape design, Pittosporum pimeleoides is used for its incredible "whorled" texture and its ability to thrive in shaded niches. It is a fantastic choice for modern native designs where it can be used as an airy, semi-transparent screen or a structural focal point in a shaded courtyard. Its glossy green leaves and dark stems provide a lush backdrop for silver-foliaged shade plants like Astelia banksii . It is an essential choice for anyone looking to create a garden that celebrates the unique and delicate flora of the upper North Island.

Seasonal Care

Spring

Apply a general-purpose native fertilizer; monitor for new growth flushes.

Summer

Provide regular watering during dry spells; ensure the mulch layer is intact.

Autumn

Optimal time for planting; collect seed capsules as they split to reveal orange pith.

Winter

Peak flowering period; enjoy the night-scented yellow and red blooms.

Pruning

Pruning Techniques

This species naturally forms a very airy, elegant shape and requires minimal pruning. If needed, light tipping of the branch ends can be done in early spring to encourage more compact growth. Remove any dead or damaged stems to maintain the plant's health. Avoid hard pruning into old wood, as it can be slow to recover. Always use sharp, sterilized tools to ensure a clean cut.

How to Grow Slender Kōhūhū

From Seed

Propagation from seed is the standard method. Collect the woody capsules when they start to split. Remove the black seeds and sow them on a tray of quality seed-raising mix. Cover with a very thin layer of grit or sieved mix. Place in a cool, bright spot. Germination can be slow and may take several months (usually 3-6 months). Seedlings should be kept in a sheltered, humid environment until they are well-established.

From Cuttings

Semi-hardwood cuttings can be taken in late summer. Select healthy, firm stems about 10 cm long. Dip the base in a rooting hormone and plant in a free-draining mix of 70% perlite and 30% peat. Maintain high humidity and provide bottom heat if possible. Roots should form within 2-3 months.

Troubleshooting Common Issues

The primary cause of failure is root rot from poor drainage. Ensure the soil is open and airy. If the leaves start to turn yellow and drop, the plant may be receiving too much water or not enough drainage. Conversely, if it is in a site that is too dry and windy, it will lose its lush appearance. Treat it as a specialist of the northern shaded forests - keep it cool, moist, and sheltered.

Pests & Diseases

Generally very healthy if its drainage and shade needs are met. Occasionally targeted by scale insects or aphids on new growth, which can be managed with horticultural oil. In very stagnant, humid air, it can sometimes suffer from powdery mildew; ensuring good airflow around the plant will prevent this.

Bonus Tip

To truly enjoy Slender Kōhūhū, plant it where you can appreciate its night-scented flowers during the winter months - perhaps near a walkway or a bedroom window. The sweet fragrance is a wonderful winter surprise.