Species Overview

Native to: Asia

Likely introduced across the global tropics through horticulture, it has become a problematic invader in the Pacific Islands and West Indies. It thrives in moist warm climates and prefers full sun and fertile soil.

Species Characteristics

Family: Lamiaceae

Habit: Shrub, up to 10 feet in height.

Leaves: Membranous, broadly ovate to triangular-ovate, 6-25 cm long, 5-25 cm wide, both surfaces sparsely to moderately strigillose, margins coarsely and irregularly dentate, apex acute, and base cordate to truncate.

Flowers: Terminal, cymose, densely many-flowered inflorescences bear fragrant flowers with purple, pink or red calyx and light pink to white corolla. stamens and ovary are usually modified into extra petals.

Fruit: Rarely form.

Distribution in Florida: South Florida and a few central Florida occurrences.

Impacts

Spreads aggressively via root suckering allowing it to invade disturbed and natural areas creating dense thickets and outcompeting native plants. While highly invasive in some places, these negative impacts have not been documented in Florida to date.

Do not plant.

If deep enough, vertical soil barriers may prevent spread.

Mechanical control is difficult: continual slashing will slow but not prevent spread. Vertical soil barriers may prevent further spread if deep enough.

The chrysomelid beetle Phyllocharis undulata is a prospective biocontrol agent (PIER). Further studies in this area are needed.

Herbicides containing triclopyr ester are suggested for Western Samoa. Work carried out in Western Samoa has shown that metsulfuron-methyl ester produces effective control. It has been recommended that the plants be cut and the new growth sprayed with herbicide. Spray young plants with a herbicide such as 3,5,6-trichloro-2-pyridinyloxyacetic acid butoxyethyl ester (PIER). Hormone-type herbicides in timely repeat applications will control this weed.