Lophomyrtus is a small genus of evergreen shrubs and trees in the myrtle family (Myrtaceae), order Myrtales, comprising just two species and one natural hybrid. The entire genus is endemic to New Zealand, making it one of the few woody plant genera wholly confined to those islands. It was formally described as a genus in 1941 and is closely related to the Australian genus Lenwebbia, sharing the characteristic of four-petalled flowers and somewhat similar foliage.
Members of Lophomyrtus are compact, bushy shrubs or small trees typically reaching up to 6 metres in height. They are particularly noted for their ornamental foliage: leaves are opposite, leathery, and may be purple, chocolate, red, or bronze-green in colour, with some species displaying a distinctive bullate (blistered or bubbly) leaf surface mottled with dark red, maroon, or purple-black markings. Flowers are white, four-merous, with numerous projecting stamens giving the bloom a showy, brush-like appearance. Fruit is a small dark red to black berry.
The two recognised species are Lophomyrtus bullata (ramarama) and Lophomyrtus obcordata (rohutu). Where their ranges overlap, they hybridise freely to produce Lophomyrtus × ralphii, a hybrid swarm that is widely cultivated and available in horticulture, valued for its colourful and varied foliage. The genus name derives from the Greek lophos (crest) and myrtus (myrtle).
Lophomyrtus bullata (ramarama) is classified as Threatened – Nationally Critical in New Zealand’s 2023 threat assessment, primarily due to the devastating impact of myrtle rust (Austropuccinia psidii), an introduced fungal pathogen that infects ramarama at higher rates than most other New Zealand Myrtaceae.
Etymology
The genus name Lophomyrtus derives from the Greek lophos, meaning “crest,” and myrtus, meaning “myrtle,” reflecting the plant’s relationship to the broader myrtle family (Myrtaceae). The species epithet bullata refers to the distinctively blistered or “bubbly” leaf surface that is the defining characteristic of ramarama.
Distribution
Lophomyrtus is entirely endemic to New Zealand, with both species occurring across the North Island and into the South Island, though L. bullata becomes scarce in the South Island south of approximately North Canterbury and Greymouth. The genus inhabits coastal to montane forest and shrubland, frequently as an understorey component of lowland podocarp riparian forest.
Ecology
Plants of Lophomyrtus grow in coastal to montane forest and shrubland, most commonly in the understorey of lowland podocarp riparian forest. They also occur in slope forest and regenerating shrubland following forest clearance. The genus is classified as facultative upland (FACU), meaning it occasionally grows as a hydrophyte but is usually found in upland, non-wetland habitats. Flowering occurs November to March, with fruiting from January to June.
Cultivation
Lophomyrtus and its hybrid L. × ralphii are grown as ornamental shrubs, valued for their colourful foliage. Plants do best in a semi-shaded position in free-draining, moist, fertile soil enriched with organic matter; they are also surprisingly drought tolerant. Full sun promotes the development of leaf colour in cultivars, but in cool climates a sheltered position is advisable. The hybrid cultivars are far more commonly available from garden centres than the wild species. Lophomyrtus bullata (ramarama) itself is rarely found in commerce but is an attractive and hardy garden subject.
Conservation
Lophomyrtus bullata (ramarama) is classified as Threatened – Nationally Critical under the New Zealand Threat Classification System (2023 assessment), a major elevation from its Not Threatened status prior to 2017. The primary driver is myrtle rust (Austropuccinia psidii), an introduced fungal pathogen that has been found infecting ramarama and its hybrids at higher rates than other Myrtaceae in New Zealand. Both ramarama and the hybrid L. × ralphii are considered seriously threatened by this disease.
Propagation
Lophomyrtus is easily propagated from fresh seed. Plants can also be grown from semi-hardwood or hardwood cuttings. Seed viability tends to decline quickly, so sowing promptly after harvest is recommended.
