Pennisetum macrourum Trin., Poaceae

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Present on Pacific Islands?  yes

Threat only at high elevations?  no

Risk assessment results:  Reject, score: 26 (Go to the risk assessment)

Common name(s): [more details]

English: African feathergrass, bedding grass, waterside reed

Habit:  grass

Description:  "Reed-like perennial from a creeping rhizome; culms 0.6-5 m high, often robust, scaberulous or occasionally pubescent below the panicle; nodes brown. Leaf-blades 10-45 cm long, 2-10 (-15) mm wide, hard, glaucous, often convolute, with a filiform tip. Panicle linear, often elongated, 6-40 cm long; rhachis cylindrical with rounded ribs, with or without peduncle-stumps, scaberulous or sometimes pubescent; involucre enclosing 1 sessile spikelet, without a distinct stipe at the base; bristles glabrous, the longest 5-20 mm. Spikelets narrowly elliptic to narrowly ovate, 2-6 mm long, acute or acuminate; lower glume up to 1 mm long, usually obtuse; upper glume 1/8-1/4 as long as the spikelet, usually acute to acuminate, occasionally obtuse; lower lemma male or barren, 3/4 to as long as the spikelet; upper lemma scarcely differing in texture from the lower" (Clayton & Renvoize, 1982; p. 689).

Description from World Grass Species.

Habitat/ecology:  "The plant prefers subhumid warm-temperature regions (usually where annual rainfall exceeds 600 mm) and normally occurs on streambanks, roadsides and pastures, often in sandy soil (Parsons & Cuthbertson, 1992, cited in Csurhes & Edwards, 1998).

In New Zealand, "Forms dense clumps that exclude other vegetation. Pastures, roadsides, wasteland and urban areas. Likes damp situations such as swamps and along the borders of streams, but can tolerate drought and establish on dry shady banks; prefers light sandy soil." (Environment Bay of Plenty Regional Council). In Australia, "infestations...were first confined to moist areas near rivers, lagoons and other low lying areas subject to flooding.  It has gradually spread beyond such places to drier, improved or unimproved areas" (Lamp et al., 1990, cited in Csurhes & Edwards, 1998; p. 185).

Propagation:  "Reproduction occurs from animal and water-dispersed seed and rhizomes" (Swarbrick & Skarratt, 1994, cited in Csurhes & Edwards, 1998; p. 185).

Native range:  Africa, Yemen (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island		U.S. Dept. Agr., Nat. Res. Cons. Serv. (2005)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia Australia (continental)	Australia (continental)	introduced invasive	Csurhes, S./Edwards, R. (1998) (p. 185) Victoria and South Australia
New Zealand New Zealand	New Zealand (country)	introduced invasive	Edgar, E./Connor, H. (2000) (p. 576) "Roadsides, grassy areas, lowland and hill country pasture, creek edges, swampy soil, sandy soil".

Comments:  On US noxious weed list and several state lists. "Naturalized in Australia and New Zealand" (GRIN).

Control: 

Physical: Dig out small infestations.

Chemical: "Roundup + Pulse. Spray prior to autumn growth or to flowering in October-December. Rate - Handgun 1 litre Roundup + 150 mls Pulse/75 litres water for older plants. Handgun 1 litre Roundup + 200 mls Pulse/100 litres water for young regrowth. Knapsack 100 mls Roundup + 20 mls Pulse/10 litres water.

Gallant and crop oil. Rate - Handgun 1000 mls Gallant + crop oil/10 litres water. Knapsack 300 mls Gallant + crop oil/10 litres water.

Spray annually to eradicate small isolated areas. Contain and reduce larger areas. Aim to contain and prevent further spread short term, and eradicate long term." (Environment Bay of Plenty Regional Council)

Additional information:  Fact sheet from Environment Bay of Plenty Regional Council.
Weed guide from the Christchurch City Council.

Additional online information about Pennisetum macrourum is available from the Hawaiian Ecosystems at Risk project (HEAR).

Taxonomic information about Pennisetum macrourum may be available from the Germplasm Resources Information Network (GRIN).

References:

Clayton, W. D./Renvoize, S. A. 1982. Gramineae (Part 3). In: Flora of tropical East Africa, R.M. Polhill, ed. Crown Agents, London.

Csurhes, S./Edwards, R. 1998. Potential environmental weeds in Australia: Candidate species for preventative control. Canberra, Australia. Biodiversity Group, Environment Australia. 208 pp.

Edgar, E./Connor, H. 2000. Flora of New Zealand, vol. V: Gramineae. Manaaki Whenua Press. .

U.S. Dept. Agr., Agr. Res. Serv. 2007. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

U.S. Dept. Agr., Nat. Res. Cons. Serv. 2005. The PLANTS Database, Version 3.5 (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.