Myoporum laetum aka New Zealand Manatoka

Taxonomy ID: 3433

Myoporum laetum, commonly known as ngaio or mousehole tree, is an evergreen shrub or small tree endemic to New Zealand. First described by Georg Forster in 1786, the species name 'laetum' means 'cheerful, pleasant or bright' in Latin.

This fast-growing plant typically reaches heights of 6-10 metres with a trunk up to 30 cm in diameter, though it can spread to 3-4 metres wide. The tree often appears dome-shaped when young but becomes more irregular as it matures and branches break off. The bark on older specimens is distinctive - light grey to brown, thick, corky, firm, and deeply furrowed.

The leaves are one of the most recognizable features of ngaio. They are lance-shaped, 52-125 mm long and 15-30 mm wide, with a somewhat fleshy, glossy texture ranging from yellow-green to dark green. When held to light, the leaves reveal numerous translucent dots - glands that make this species readily distinguishable from other Myoporum species. The leaf edges have small serrations on approximately the outer half, and new growth is notably very glossy, dark, and sticky.

Flowers appear in axillary clusters of 2-6 blooms. Each flower is white with small purple spots and features 4 stamens. The flowering period varies by hemisphere - October to January in New Zealand (Southern Hemisphere) and May to June when grown in Northern Hemisphere locations. The fruits are pink drupes approximately 6-9 mm in diameter, borne on stalks, ripening from December to June in its native range.

Ngaio is endemic to New Zealand, naturally occurring on the Three Kings Islands and throughout the North and South Islands, extending as far south as Otago. It is also found on the Chatham Islands, where populations are scarce and likely naturalized. The species thrives in coastal to lowland forests and is often found in pure stands or associated with nikau palms (Rhopalostylis sapida). It sometimes grows well inland, particularly in areas like Hawke's Bay, Rangataiki, and Wairarapa.

The plant is highly valued for its exceptional tolerance to coastal conditions, being very resistant to maritime exposure and salt spray. This makes it an excellent choice for coastal gardens and windbreaks. However, an important caution must be noted: all parts of the plant contain ngaione, a liver toxin that is poisonous to livestock including horses, cattle, sheep, and pigs. The compound has antibacterial properties but requires careful handling around animals.

Myoporum laetum has been widely introduced beyond New Zealand to regions including California, Mediterranean countries (Spain, France, Italy, Portugal), North Africa, South Africa, and parts of South America. In California, it has become invasive with a 'Limited' rating from the California Invasive Plant Council, as dense stands can shade out native vegetation due to heavy seed production. The myoporum thrips (Klambothrips myopori) has been introduced as a biological control agent to manage its spread.

Common names

New Zealand Manatoka, Ngaio Tree, Myoporum

More information about New Zealand Manatoka

How big does Myoporum laetum grow?

Fast

Myoporum laetum is a fast-growing evergreen shrub or small tree that typically reaches 6-10 metres in height with a spread of 3-4 metres. The trunk can grow up to 30 cm in diameter. Young trees often have a dome-shaped form, but mature specimens become more irregular as branches break off over time. There are also naturally occurring decumbent (prostrate) forms that spread 2-4 metres across rather than growing tall.

What soil does Myoporum laetum need?

pH: Adaptable Any soil

Myoporum laetum is highly adaptable to different soil types and will grow in light (sandy), medium (loamy), or heavy (clay) soils. The plant accepts a wide pH range from mildly acidic through neutral to mildly alkaline.

What humidity does Myoporum laetum prefer?

Myoporum laetum is not particularly demanding regarding humidity levels. As a coastal species native to New Zealand, it naturally tolerates moderate to high humidity and is extremely resistant to maritime exposure and salt spray. However, it also performs well in drier conditions once established, making it adaptable to various climates within its hardiness range.

Does Myoporum laetum need fertilizer?

Myoporum laetum has modest fertilizer requirements. As a fast-growing plant that thrives in various soil types including poor coastal soils, it doesn't require heavy feeding. A balanced slow-release fertilizer applied in spring can support growth, but the plant generally performs well without regular fertilization once established. Avoid over-fertilizing as this can promote excessive soft growth.

What temperature range suits Myoporum laetum?

Myoporum laetum is hardy in USDA zones 9-11, tolerating minimum temperatures down to approximately -6°C (20°F). It thrives in subtropical to warm temperate climates and is frost-tender when young, though established plants can handle light frosts. The species grows in the subtropical biome and performs best in mild, coastal climates similar to its native New Zealand habitat.

How do you propagate Myoporum laetum?

Myoporum laetum propagates easily from both seed and semi-hardwood cuttings. For seed propagation, remove seeds from the fruit and endocarp for better germination rates. Seeds can take several months to germinate, but scarifying the seed coat with a knife or sandpaper reduces germination time. For cuttings, take semi-hardwood material and use rooting hormone for best results. Fresh seed germinates most readily.

When and how does Myoporum laetum flower?

🌸 October-January

Myoporum laetum produces attractive white flowers with distinctive small purple spots, appearing in axillary clusters of 2-6 blooms. Each flower has 4 stamens. In its native New Zealand (Southern Hemisphere), flowering occurs from October to January, while in Northern Hemisphere locations it blooms May to June. The flowers are followed by pink drupe fruits approximately 6-9mm in diameter that ripen from December to June.

How should you prune Myoporum laetum?

Myoporum laetum responds well to pruning and can be maintained as a hedge, screen, or shaped tree. Prune in late winter or early spring before new growth begins. The plant tolerates hard pruning if size reduction is needed. Regular pruning helps maintain a compact shape, as mature specimens can become irregular when branches break off naturally. Remove dead or damaged wood as needed throughout the year.

Can Myoporum laetum be grown outdoors?

🇺🇸 USDA 9-11

Myoporum laetum is exclusively an outdoor plant, thriving in USDA zones 9-11. It excels in coastal gardens due to its exceptional tolerance of maritime exposure and salt spray. The species requires full sun and cannot grow in shade. It makes an excellent windbreak, screen, or specimen tree in mild climates. In areas where it's invasive (like California), consider native alternatives or manage carefully to prevent spread.

What pests and diseases affect Myoporum laetum?

The most significant pest is the myoporum thrips (Klambothrips myopori), which causes leaf distortion and galling. Paradoxically, this thrips can act as biological control where the plant is invasive. In its native New Zealand, the main conservation concern is hybridization with introduced Tasmanian boobialla rather than pests. Generally, this is a hardy plant with few serious pest or disease problems when grown in appropriate conditions.

Does Myoporum laetum have a scent?

Yes, Myoporum laetum has resinous, aromatic leaves and fragrant flowers. The leaves contain oil glands (visible as translucent dots when held to light) that give them their distinctive scent. The crushed leaves have a strong resinous smell, and this aromatic quality is part of what makes the plant effective as an insect repellent, particularly against mosquitoes.

Is Myoporum laetum edible?

🍎 Rating 1/5 🥗 Fruit

The fruits of Myoporum laetum are edible and can be eaten raw or cooked. They are small pink drupes about 6-9mm in diameter with a mild flavor. However, caution is strongly advised because all other parts of the plant contain ngaione, a liver toxin that is poisonous to livestock and potentially harmful to humans. The edibility rating is only 1 out of 5, indicating minimal food value.

What are the medicinal uses of Myoporum laetum?

💊 Rating 1/5

Myoporum laetum has limited traditional medicinal uses, rated 1 out of 5 for medicinal value. The bark has been used to treat ulcers, while other preparations serve as odontalgic (treating toothache) and vulnerary (promoting wound healing) remedies. Interestingly, the ngaione compound that makes the plant toxic also has antibacterial properties. Due to the presence of liver toxins, any medicinal use requires extreme caution.

What other uses does Myoporum laetum have?

🔧 Rating 3/5

Myoporum laetum is rated 3 out of 5 for other uses. Its most notable non-ornamental use is as an insect repellent - the aromatic leaves are effective against mosquitoes. The plant excels in landscape applications as a windbreak, hedge, screen, or specimen tree, particularly in coastal areas where its salt tolerance is invaluable. The wood is not typically used commercially, but the plant's dense growth makes it valuable for shelter and privacy screening.


More info:
Wikipedia GBIF