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Juncus acutus L.
Spiny Rush

Sp.Pl. 1:325 (1753)
Conservation Code
Not threatened
Naturalised Status
Alien to Western Australia
Name Status

Robust rhizomatous, perennial, herb, to 1.5 m high. Fl. brown/green, Aug to Nov or May. Grey sand, loam, often saline. Creeks, soaks.

Amanda Spooner, Descriptive Catalogue, 12 February 2004


IBRA Regions
Avon Wheatbelt, Esperance Plains, Geraldton Sandplains, Jarrah Forest, Swan Coastal Plain.
IBRA Subregions
Dandaragan Plateau, Geraldton Hills, Katanning, Lesueur Sandplain, Merredin, Northern Jarrah Forest, Perth, Recherche, Southern Jarrah Forest.
IMCRA Regions
Local Government Areas (LGAs)
Beverley, Boddington, Bridgetown-Greenbushes, Brookton, Busselton, Coorow, Corrigin, Cuballing, Cunderdin, Dandaragan, Denmark, Esperance, Fremantle, Goomalling, Gosnells, Greater Geraldton, Katanning, Kojonup, Narrogin, Northam, Northampton, Perth, Rockingham, Swan, Tammin, Toodyay, Victoria Plains, Wagin, West Arthur, Wickepin, Williams, Wongan-Ballidu, York.

Management Notes (for the Swan NRM Region)

Alternative Names. Spiny Rush, Cultivation Rush.

General Biology. Growth form. Sedge. Life form. Perennial. Reproduction. Primarily by seed, also crown fragments. Dispersal. Water, mud, soil movement, machinery, inappropriate or inadvertant plantings. Seedbank persistence. Seeds remain viable in laboratory conditions for 4 years, thought to be much shorter in the field. Fire response. Rhizomes are able to resprout after fire..

Notes. Naturalised in other Australian states and New Zealand. Establishes in disturbed natural ecosystems such as riparian vegetation and wetland areas. Once established, completely covers an area and eliminates all other vegetation, makes areas impenetrable to stock and humans because of the sharp spines, can restrict flow of water causing flooding, provide harbour for introduced fauna, particularly rabbits. Has allelopathic anti-aglae compounds. Tolerant of water logging (occurs along waterways), moderate salinity and drought. Long lived. Wind pollinated. Able to flower and set seed from two years of age onwards. Prefers light sands to loam although can also grow in heavy clay soil. Is a polymorphic species with numerous varieties described. Seed has high germination rates in light , however no germination occurs in the dark. Has 100% germination in freshwater, however this decreases with higher salinity, although ungerminated seeds are not damaged by salt or periods emersed in salt water. Known to hybridise with the native Juncus kraussii, which has marginally greater salinity tolerance. Has the potential to displace J. kraussii, particularly in areas that receive regular freshwater input. Similarly, periods of heavy rainfall, which reduce soil salinity, may help colonisation of new areas.

Additional information. Origin. Europe, Mediterranean, south-west Asia, southern and northern Africa, northern and southern America. History of use/introduction. It is unknown how Spiny Rush arrived in Australia. The earliest herbarium specimens were collected in the Sydney area.. Similar native species. Juncus kraussii, J. pallidus.

Suggested method of management and control. controlling infestations early and preventing further spread is the most effective form of management. Management programs using mechanical controls, chemicals, cultivation, altering salinity and drainage, and pasture management measures have been proposed. Spiny Rush may be dug out effectively, as the plant is shallow-rooted. The roots need to be severed and the top growth may also be burnt. The plant likes damp situations so improving drainage may help to reduce populations, but this would not be a suitable control measure where it is a weed in natural habitats such as wetlands. Chemical control is often impractical because of the difficulty of application to dense patches; therefore, mechanical removal of the existing growth, although costly, is often the most practical starting point in a control program, Read the manufacturers' labels and material safety data sheets before using herbicides. For further information consult the Australian Pesticides and Veterinary Medicines Authority to determine the status of permits for your situation or state.

Management Calendar

Calendar Type Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Comments
Active Growth             Y Y Y Y Y Y  
Germination O O O O Y Y O O O O O O  
Flowering                   Y Y Y  
Fruiting Y Y                   Y  
Manual Removal Y Y Y Y Y Y Y Y Y Y Y Y  
Herbicide Treatment Y Y Y O O       O Y Y Y Depends on presence of water

Legend: Y = Yes, regularly, O = Occasionally, U = Uncertain, referred by others but not confirmed.



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