Species Overview

Native to: West Indies, tropical Central and South America, 

West Indian marsh grass is occasionally found growing in wet pastures from the central peninsula to Collier county. It is native to the West Indies and blooms in the fall (Wunderlin, 2003).

Species Characteristics

• Family: Poaceae
• Habit: : Robust perennial grass from stolons; stems floating, creeping, or ascending to 1 m (3 ft) or more in height, sparingly branched, rooting at the lower nodes; stems pithy, not hollow
• Leaves: blades flat, to 35 cm (14 in) long and to 4 cm (1.6 in) wide, cordate at the base and clasping the stem; glabrous but with long hairs on lower margins
• Flowers: Anthers 3; 1.1-1.2 mm long
• Infloresence: terminal panicle, dense and spike-like, about 8 mm (0.3 in) wide and to 50 cm (20 in) long; spikelets short stalked, 3.3-4.3 mm long, scabrous on the veins, often opened slightly at the apex
• Fruit: spike-like, densely flowered panicle, to 26 cm (10 in) long and ~1 cm (0.4 in) wide; spikelets short-stalked
• Seeds: 3-4 mm
• Distribution in Florida: central and south

West Indian marsh grass may be confused with the native American cupscale (Sacciolepis striata) which has a similar inflorescence. However, Hymenachne stems contain white pith, whereas most grass stems are hollow.

Impacts

West Indian marsh grass has been found to be displacing native maidencane (Panicum hemitomon) communities in central and south Florida. It forms dense colonies and has become increasingly difficult to controla, especially long drainage canals of south central Florida.

West Indian marsh grass is not recommended by UF/IFAS. The UF/IFAS Assessment lists as West Indian marsh grass as invasive/no use in all parts of Florida. FLEPPC lists it as a Category l invasive species due to its ability to invade and displace native plant communities.

Once established, West Indian marsh grass is extremely difficult to control. 

 Scattered plants may be removed manually, however all stolons and roots must be removed to prevent regrowth. 

There are no known biological control agents for West Indian marsh grass.