Andropogon virginicus L., Poaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results: 

Reject, score: 13 (Go to the risk assessment (Australia)).
High risk, score:  20 (Go to the risk assessment (Pacific)).

Common name(s): [more details]

English: broomsedge, broomsedge bluestem, chalky bluestem, whisky grass, yellow bluestem

Habit:  grass

Description:  "Perennial tall bunchgrass with tufted stems, 50-100 cm tall, branches 1-3 at node.  Leaves:  Leaf-sheaths more or less tuberculate-hirsute on the margins with long usually lax hairs; ligule yellow-brown, membranous, truncate, white-fringed at edge; blades 40 cm long or less, 2-5 mm wide, rough or roughish, hirsute on the upper surface near the base; spathes 3-5 cm long, extending beyond the racemes.  Racemes:  2 (-3-4), 2-3 cm long.  Spikelets:  Sessile spikelet 3-4 mm long, twice to half again as long as the internode, the awn straight, 10-15 mm long; pedicellate spikelet wanting or rarely present as a minute scale, pedicel exceeding the sessile spikelet.  Flowers:  Either sessile and hermaphrodite, or stalked and staminate, sterile or not developed"  (Cronk and Fuller, 1995; pp. 67-69).

Description from GrassBase.

Habitat/ecology:  Subhumid to humid subtropical areas on a wide range of soils.  Dried material contributes to fire hazard, and reproduction is encouraged by fire.  In Hawai‘i, "common and often dominant along roadsides and in disturbed dry to mesic forest and shrubland, especially on ridges, 50-1,200 m"  (Wagner et al., 1999; pp. 1497, 1904); "in disturbed grassland and scrub on Oahu from about 50-250 m, on red clay soils in places where the native forest vegetation has been replaced by introduced woody and herbaceous plants' (Cronk & Fuller, 2001, p. 68). "Forms nearly monotypic stands in poor pastures and in open and disturbed conservation land.  Poor forage.  A fire hazzard:  (Motooka et al., 2003).  In Australia, "has invaded communities which are extremely deficient in nutrients and were thought for this reason to be uninvasible"  (Cronk & Fuller, 2001, p. 68).  Highly flammable and alters the fire regime in areas where it has invaded (Cronk & Fuller, 2001, p. 68).

Propagation:  Seed.  "The awned seed is well adapted to catch in wool and fur as well as in clothing and other fibrous materials".  May also spread on mud on machinery.

Native range:  North America, Central America, West Indies; cultivated and naturalized elsewhere (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	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1497) Voucher cited: Lee 65 (BISH)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Imada, Clyde T./Staples, George W./Herbst, Derral R. (2000) (p. 14) Voucher cited: C. Imada, W. Char & C. Morden 99-10 (BISH)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Snow, Neil/Lau, Alex (2010) (pp. 48-49) Voucher cited: D.H. Lorence & A. Stone 8384 (BISH, PTBG, K, US)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Hughes, Guy D'Oyly (1995) (p. 8) East Maui. Voucher cited: Higashino 9360 (BISH) Sparingly naturalized in dieback forest and dominating disturbed areas of lowland mesic shrubland.
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Oppenheimer, Hank L./Meidell, J. Scott/Bartlett, R. T. (1999) (p. 9) West Maui. Voucher cited: Oppenheimer H99804 (BISH) In a wide range of habitats, including bogs, wet and mesic forests, pastures and roadsides.
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Hughes, Guy D'Oyly (1995) (p. 8) Voucher cited: Hughes s.n. (BISH) Colonizes disturbed mesic shrubland and dominates many disturbed areas, from 600-1000 m.
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1497)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Snow, Neil/Lau, Alex (2010) (pp. 48-49) Vouchers cited: G. Spence 210 (BISH), G. Tam s.n. (BISH 641686)

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)		Hafliger, Ernst/Scholz, Hildemar (1980) (p. 8)
Australia Australia (continental)	Queensland	introduced invasive	Queensland Herbarium (2002) (p. 1)
Central America Central America (Pacific rim)	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Honduras (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Panama (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 191)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Edgar, E./Connor, H. (2000) (p. 600) "Roadsides and along railway line".
South America (Pacific rim) South America (Pacific rim)	Colombia	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Canada Canada	Canada	native	U.S. Dept. Agr., Agr. Res. Serv. (2013) Ontario
United States (continental except west coast) United States (other states)	United States (other states)	native invasive cultivated	U.S. Dept. Agr., Agr. Res. Serv. (2013) Also cultivated and naturalized.
United States (continental except west coast) United States (other states)	USA (Florida)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Comments:  A serious problem in Hawai‘i. On French Polynesia exclusion list.

Control: 

Physical:  "Grazing management is probably the only practical way to control grass weeds in pastures"  (Motooka et al., 2003).

Chemical: Effective control can be achieved by application of bromacil, hexazinone, tebuthiuron, bromacil & Diuron, and buthidazole (Cronk & Fuller, 2001; pp. 67-69).

"Research in Oklahoma indicates that glyphosate on intact old growth not effective, but very effective only after removal of old growth e.g. by fire. However, seedlings readily reinfested the treated area. Glyphosate effective for controlling broomsedge but thorough application to live foliage is critical. HAVO staff controlled broomsedge with foliar application of glyphosate at 1% in water (Chris Zimmer, HAVO)"  (Motooka et al., 2003).