The genera Brachiaria and Urochloa are closely related, and the two are united by some authors. See Veldkamp, Taxon 45 (1986) 319. However, this unification is not accepted by all authors - see Flora of China Vol 22 pp520-523 2006. We are following the treatment in the Flora of China and the Kew 'World Checklist of Selected Plant Families', and treating the two genera as distinct[].
Brachiaria and Urochloa are distinguished mainly by habit, Urochloa having rather more flattened, cuspidate spikelets enclosing a pronounced mucro from the upper lemma. The different spikelet orientation is also characteristic, though not obvious when the spikelets are paired. In Urochloa the lower glume faces outward, whereas in Brachiaria it lies against the rachis[]..

Common Name: Giant Couch

General Information

Brachiaria mutica is an evergreen, perennial grass spreading freely from a vigorous, stoloniferous rootstock to form a colony of culms 100 - 200cm tall. The stout culms have a trailing habit, they often root at the lower nodes. A vigorous plant, individual stolons can be up to 5 metres long[, ].
This is a forage grass (Para Grass) widely cultivated in tropical regions of the world and often found as a naturalized escape. It is often used as a ground cover and soil stabilizer.
This species has been introduced throughout much of the tropics and may still be spreading, it is not subject to any known threat. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

None known

Botanical References

,

Range

Probably originating in Tropical Africa, it has spread through cultivation to be a weed of many regions in the tropical and warm temperate zones

Habitat

Swampy and wet places such as marshes, rice fields ,ditches and riversides, sometimes forming floating mats; also in open, more or less lightly shaded places such as coconut plantations; sandy beaches; at elevations up to 1,530 metres[, ].

Properties

Weed Potential	Yes
Conservation Status	Least Concern
Other Uses Rating
Habit	Evergreen Perennial
Height	1.50 m
Pollinators	Wind
Cultivation Status	Cultivated

Cultivation Details

Brachiaria mutia is a plant of the warm, moist tropics, usually at low elevations[]. It grows best in areas where annual daytime temperatures are within the range 21 - 30°c, but can tolerate 15 - 46°c[]. It prefers a mean annual rainfall in the range 1,200 - 2,000mm, but tolerates 900 - 4,100mm[].It prefers to grow in flat, poorly drained, seasonal floodplains or high rainfall environments (tolerating a mean annual rainfall from 870 - 4,100mm) in tropical and subtropical regions of the world[]. It is also adapted to high temperatures (20 - 35°c), but growth is restricted by temperatures below 15°c[].
Prefers a position in full sun, tolerating light shade. The plant grows best in poorly drained (swampy or periodically waterlogged) soils and other wet sites, also succeeding in well-drained soils in areas of high rainfall. It can grow in water up to 120cm deep in the tropics[]. It is well adapted to a wide range of soil types, from sandy to clay, preferring soils of medium to high fertility[]. It is tolerant of moderate salinity, a low pH down to 4.5 and the high levels of trace elements normally produced under water-logged conditions[]. Plants are probably tolerant of maritime exposure[, ]. Prefers a pH in the range 5 - 6, tolerating 4.3 - 7.7[].
Brachiaria mutica is a fast-growing perennial grass, capable of forming very dense infestations that smother riverbanks, wetlands, and floodplain vegetation, and also floating out over the water surface which reduces areas available for waterfowl and water-birds. It is widely naturalized in tropical and subtropical regions of the world where it was originally introduced as a fodder grass. Now, this species is considered one of the world’s worst weeds in areas such as the United States, Australia, Mexico, and Central America. It has been intentionally introduced as a pasture grass because its ability to establish on poorly drained (swampy or seasonally waterlogged) soils as well on free-draining soils in high rainfall environments. It competes aggressively with other plants, with fast growth, high productivity, and allelopathic abilities that allow it to form dense stands[]. The plant can become a weed in irrigation ditches and drains[].
The plant is a short-day species that flowers most prolifically in humid tropical environments at latitudes from 10 - 20° north and south. Little or no flowering takes place at subtropical latitudes[].

Edible Uses

None known

Medicinal

None known

Agroforestry Uses:

The plant is used as a ground cover in coconut and sugarcane plantations, though once established it is difficult to eradicate[].
It is used in reclamation areas, sand dunes etc to prevent soil erosion, but once present, it can be difficult to eradicate[]. It is particularly suited to erosion control along river banks[].

Other Uses

None known

Propagation

Seed -

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