Juncus acutus L., Juncaceae

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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Risk assessment results:  Reject, score: 15 (Go to the risk assessment)

Common name(s): [more details]

English: sharp rush, spiny rush

Habit:  rush

Description:  "Very stout, forming dense prickly tufts; rhizomes stout, woody. Stems (40) -60-100cm x 1.5-5 mm, very stiff and erect, smooth, light green. Basal sheaths shining dark red-brown. Leaves 1-2, basal, terete, similar to stem, with very pungent tip. Inflorescence large, compact 5-15 cm long. Flowers crowded. Tepals c. 3 mm long, ± equal, very hard, outer mucronate, inner truncate to emarginate with wide membranous margin at tip. Stamens 6. Capsule 4.5-5 mm long, much > tepals, ovoid, abruptly tapered, acute, reddish-brown to brownish-orange. Seeds with distinct tails.  Recognised by the dense, robust, stiff, prickly clumps, large congested heads, large reddish-brown to brownish-orange capsules much > tepals, and long-tailed seeds"  (Healy & Edgar, 1980; p. 99).

Habitat/ecology:  "Coastal flats and saline areas, grassland, riparian habitats, disturbed sites.  Native habitats of this plant include sandy seashores, drier parts of salt marshes, and other sandy places.  It is a highly variable species with numerous varieties.  The large and dense tussocks lead to dense patches that support little native vegetation.  In infested watercourses, the plant restricts water flow"  (Weber, 2003; p. 223).

In the United States, "moist saline habitats and alkaline seeps; below 300 m"  (Flora of North America online).  Coastal saline flats where naturalized in New Zealand  (Healy & Edgar, 1980; p. 99).

Propagation:  "Seeds are dispersed mainly by water"  (Weber, 2003; p. 223).

Native range:  Northern Africa, Europe, western Asia, southwestern USA, northern Mexico, Bermuda, southern South America; naturalized in Australia and New Zealand (GRIN).

Presence:

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)	New South Wales	introduced invasive	National Herbarium of New South Wales (2013) A weed of damp areas in temperate regions. Naturalised
Australia Australia (continental)	Australia (continental)	introduced invasive	National Herbarium of New South Wales (2013) South Australia, Tasmania, Victoria, Western Australia Naturalised
Australia Australia (continental)	Northern Territory	introduced invasive	National Herbarium of New South Wales (2013) Naturalised
Australia Australia (continental)	Queensland	introduced invasive	National Herbarium of New South Wales (2013) Naturalised
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013) Baja Norte, Puebla
New Zealand New Zealand	New Zealand (country)	introduced invasive	Healy, A. J./Edgar, E. (1980) (p. 99) Coastal saline flats.
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast) United States (west coast states)	USA (California)	native	U.S. Dept. Agr., Nat. Res. Cons. 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
United States (continental except west coast) United States (other states)	United States (other states)	native	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013) Arizona, Nevada

Control: 

Physical:  "Single tussocks may be removed mechanically.  Cutting at ground level is used for larger infestations, and a follow-up programme is necessary to control regrowth and emerging seedlings".

Chemical:  "Effective herbicides are 2,4-D ester or hexazinone"  (Weber, 2003; p. 223).