Invasiveness Assessment - Spiny rush (Juncus acutus) in Victoria (Nox)
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Plant invasiveness is determined by evaluating a plant’s biological and ecological characteristics against criteria that encompass establishment requirements, growth rate and competitive ability, methods of reproduction, and dispersal mechanisms.
| Each characteristic, or criterion, is assessed against a list of intensity ratings. Depending upon information found, a rating of Low, Medium Low, Medium High or High is assigned to that criterion. Where no data is available to answer a criterion, a rating of medium (M) is applied. A description of the invasiveness criteria and intensity ratings used in this process can be viewed here. |
The following table provides information on the invasiveness of Spiny rush.
A more detailed description of the methodology of the Victorian Weed Risk Assessment (WRA) method can be viewed below:
Victorian Weed Risk Assessment (WRA) method (PDF - 630 KB)
Victorian Weed Risk Assessment (WRA) method (DOC - 1026 KB)
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Common Name: Spiny rush
Scientific name: Juncus acutus
| Question | Comments | Reference | Rating |
| Establishment | |||
| Germination requirements? | Seeds germinate at most times of the year. | P & C (1992) | H |
| Establishment requirements? | Mostly occurs in ‘open’ habitats in Australia. However, occurs with willow riparian vegetation and sycamore woodland in Dan Diego But. Subsp. Of J. acutus. | P & C (1992) Reiser (1994) | ML |
| How much disturbance is required? | Establishes in minor disturbed natural ecosystems e.g. riparian vegetation and wetland areas. | Carr et al (1992) | MH |
| Growth/Competitive | |||
| Life form? | Semi aquatic. Occurs in swamps, creeks and wetlands. | Sainty & Jacobs (1981) Carr et al (1992) | H |
| Allelopathic properties? | None described. |  | L |
| Tolerates herb pressure? | Not readily eaten by grazing animals. | P & C (1992) | MH |
| Normal growth rate? | Once established completely covers an area and eliminates all other vegetation. | P & C (1992) | H |
| Stress tolerance to frost, drought, w/logg, sal. etc? | Tolerant of water logging (occurs along waterways), salinity (occurs in saline wetlands), drought? (Survives in desert environments). | P & C (1992) Carr et al (1992) | MH |
| Reproduction | |||
| Reproductive system | Reproducing by seeds and from rhizomes. | P & C (1992) | H |
| Number of propagules produced? | Seeds numerous in each capsule. 200 seed capsules x 20 seeds per capsule = 4,000 seeds per plant. (Refer to pic. P & C 1992 p. 82). | P & C (1992) | H |
| Propagule longevity? | | | M |
| Reproductive period? | Plants are long lived. Do not flower until at least two years old, so would produce seeds at least 3-10 years. | P & C (1992) | MH |
| Time to reproductive maturity? | Plants do not flower until at least two years old. | P & C (1992) | ML |
| Dispersal | |||
| Number of mechanisms? | Seeds – contaminant of agricultural produce, machinery, vehicles, water, mud etc. Also dispersed by rhizomes. | P & C (1992) | MH |
| How far do they disperse? | As riparian sp. many seeds would be dispersed by water movements, which is likely to be 20-200 m. Plus seed adhering to animals would also be dispersed 20-200 m. | | ML |
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© The State of Victoria, 1996 - 2012.
This document was last reviewed on 26/09/2011