Photo: Betsy H. Gagne

Overview

Native to Central and South America, miconia was introduced to Hawai`i in the 1960s as an ornamental. It forms dense stands shading out native vegetation with its large leaves, suppressing the growth and regeneration of native species in the understory. Large populations have become established on Maui and Big Island, with smaller populations on O`ahu and Kauai. It is considered to be the greatest single threat to Hawaii’s remaining wet forest. Miconia is the most invasive and damaging alien plant of many Pacific island rain forests. Its shallow roots cannot hold the forest floor’s exposed soil, which erodes into the ocean, damaging coral reefs. Occurs in coastland, disturbed areas, natural and planted forests, riparian zones, scrub/shrub lands, urban areas and wetlands.

Description

A medium-sized tree that grows 20 to 50 feet in height; leaves are opposite large (up to 3 feet long) dark green above with three prominent pale green veins, purple-blue beneath. Small white flowers, slightly fragrant, arranged in large panicles; purple-black fleshy berries when mature. A single mature plant can produce millions of seeds/year which are dispersed by non-native frugivorous birds. Shallow root system.

Birds Affected

Hawaii’s native forest birds, honeycreepers

Control

Hand removal (uprooting) of seedlings and juvenile plants is an effective method. For older trees, cut-stump treatment using herbicides is necessary to prevent re-sprouting. In large concentrations, canopy removal can result in spectacular germination of the seed bank. All known individuals on O`ahu and Kaua`i have been killed and periodic searches are made in neighboring areas to ensure that any new seedlings are quickly removed. The Hawaii Department of Land and Natural Resources has published hotlines for each island.