Invasiveness Assessment - Khaki weed (Alternanthera pungens) 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 Khaki weed.
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 - 1 MB)
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Common Name: Khaki weed
Scientific name: Alternanthera pungens
| Question | Comments | Reference | Rating |
| Establishment | |||
| Germination requirements? | Seeds germinate after spring and summer rains. Roots producing new aerial growth annually. | P & C (1992) | MH |
| Establishment requirements? | Can establish under moderate canopy, i.e. occurs in orchards and crops. | P & C (1992 | MH |
| How much disturbance is required? | Established in pastures. | P & C (1992 | MH |
| Growth/Competitive | |||
| Life form? | A prostrate creeping perennial (occasional annual) herb. Also geophyte – stems can take root at nodes. | P & C (1992 | ML |
| Allelopathic properties? | None described. |  | L |
| Tolerates herb pressure? | Not really eaten, although at times young plants are moderately palatable to sheep and are consumed. | P & C (1992 | MH |
| Normal growth rate? | “Establishes occasionally in native pastures where it out-competes most other species”. | P & C (1992 | H |
| Stress tolerance to frost, drought, w/logg, sal. etc? | Tolerance t drought, water logging (occurs in wetlands). | P & C (1992 | ML |
| Reproduction | |||
| Reproductive system | Reproducing by seed, roots and stems taking root at nodes. | P & C (1992 | H |
| Number of propagules produced? | “Seeds prolific and viable for years”. (Web page). | | M |
| Propagule longevity? | See above comment “years”. But number years unknown. | | M |
| Reproductive period? | Forms dense monocultures. See picture P & C (1992) p. 159. | P & C (1992 | H |
| Time to reproductive maturity? | Seeds germinate spring/summer Plants flower and seed next summer and autumn. | P & C (1992 Anon. | MH |
| Dispersal | |||
| Number of mechanisms? | Prickly burrs attach to animals, equipment, clothing and tyres. Also by water and wind, wool, hay and impure grain from affected areas. | P & C (1992 | MH |
| How far do they disperse? | Many propagules will reach 200-1,000 m due to prickly burr that can even attach to car tyres and travel long distances. | | MH |
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