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Megathyrsus spp.
guinea grass
Overview
Megathyrsus is a small genus of tall tropical grasses in the family Poaceae, most familiar as M. maximus, Guinea grass, a robust tussock grass native to Africa. Plants form dense clumps of arching leaf blades and flowering stems that reach 3–10 ft (0.9–3 m) tall, occasionally taller in rich soil. The leaf blades are broad, flat, and rough-edged, to about 1.4 in (35 mm) wide, rising from a knotty base. Airy, branching panicles up to 18 in (45 cm) long carry many small spikelets that ripen to straw and shed abundant seed. As a fast-growing C4 grass, it grows vigorously in warmth and responds strongly to nitrogen, which has made it a major pasture and forage grass across the tropics. The same vigor makes it a serious invasive weed in many regions, including parts of Australia, the Americas, and the Pacific, where it crowds out native plants and carries intense fires. It tolerates a wide range of soils, drought once established, and partial shade. Frost cuts back the top growth, and hard freezes kill it. Tussocks regrow rapidly from the crown after cutting, grazing, or burning.
Native Range
Megathyrsus maximus is native to tropical and subtropical Africa, including the Arabian Peninsula. It has been introduced across the warm regions of the world as a forage grass and is now naturalized widely.Suggested Uses
Grown chiefly as a tropical pasture and cut-and-carry forage grass for cattle and other livestock. It is also used for erosion control and as a tall screen or clump grass in large warm-climate gardens. Outside managed use it is widely regarded as an environmental weed.How to Identify
Appearance
Size & Dimensions
Height3' - 10'
Width/Spread2' - 5'
Bloom Information
Flowering and seeding run mainly through the warm, wet season and can continue much of the year in the tropics. The airy panicles release large quantities of light, wind- and animal-dispersed seed. Plants flower within months of germinating, which speeds their spread.
Detailed Descriptions
Flower Description
green to strawFoliage Description
green to blue-greenGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight