Family: Scrophulariaceae
Myoporum laetum (ngaio, mousehole tree) is an evergreen shrub or small tree endemic to New Zealand. Ngaio has a long history of use by Māori (the indigenous people of New Zealand) who used its bark for medicinal purposes, leaves as a mosquito and sandfly repellent, and its wood for making fishing gear, tool handles, and weapons. The tree is also used for erosion control and as a windbreak.
Ngaio is considered an invasive exotic species by the California Exotic Pest Plant Council. This plant is capable of spreading far by birds who are attracted to its seeds. It forms dense stands that outcompete other vegetation. The leaves are also toxic and can be fatal to livestock. Additionally, the plant is a host to Klambothrips myopori, a thrips pest that can also affect the native Hawaiian plant Myoporum sandwicense (Naio). For this reason the plant is considered high risk.
High Risk Traits:
- Naturalized in California and elsewhere
- An environmental weed
- Toxic to animals, and humans if ingested
- Host to Klambothrips myopori, a thrips pest that can also affect the native Hawaiian Myoporum sandwicense
- Increases fire risk in fire prone areas
- Can from dense monocultures that exclude other vegetation
- Tolerates many soil types
- Spreads by bird-dispersed seed that can also be spread unintentionally by water or soil movement, and intentionally by people
- Hybridizes with other Myoporum species
- Seeds may persist in soil for years
- Will resprout from stump if cut or damaged
Low Risk Traits:
- Unarmed
- Requires full sun
- Does not spread vegetatively
- Herbicides can provide effective control
