Invasiveness Assessment - Angled onion (Allium triquetrum) 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 Angled onion.
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: Angled onion
Scientific name: Allium triquetrum
| Question | Comments | Reference | Rating |
| Establishment | |||
| Germination requirements? | Seeds and bulbs germinate in autumn. | P & C (1992) | MH |
| Establishment requirements? | Occurs in woodlands and ‘shady places’. | Carr et al (1992) Tutin et al (1980) | MH |
| How much disturbance is required? | Establishes in minor disturbed ecosystems (e.g. riparian, wetlands & woodlands), and pastures. | Carr et al (1992) P & C (1992) | MH |
| Growth/Competitive | |||
| Life form? | Bulbous perennial herb. Geophyte. | P & C (1992) | ML |
| Allelopathic properties? | None described. |  | L |
| Tolerates herb pressure? | Consumed – response unknown. However, probably recovers quickly as it is noted as being z’ a very persistent weed which may take some time and intensive effort to completely eradicate”. (NCC). | | MH |
| Normal growth rate? | Does not compete strongly with crops and improved pastures. Can completely smother and replace native ground cover vegetation. | P & C (1992) NCC | MH |
| Stress tolerance to frost, drought, w/logg, sal. etc? | Tolerant of water logging (occurs on poorly drained soils along watercourses). Also, assumed tolerant of frosts (occurs on slopes of Great Dividing Range and the Dandenong Ranges). | P & C (1992) | ML |
| Reproduction | |||
| Reproductive system | Reproducing by seeds and bulbs. | P & C (1992) | H |
| Number of propagules produced? | Probably < 50 seeds produced by each small bulb. (See picture Hyde-Wyatt & Morris 1980 and O’Neill 1962). | Hyde-Wyatt (1980) O’Neil (1962) | L |
| Propagule longevity? | ? | | M |
| Reproductive period? | Provides a complete ground cover in some areas. - forms monocultures. | P & C (1992) | H |
| Time to reproductive maturity? | Year one - Seeds germinate. Year two - Bulbs germinate. Year three - Seeds produced by bulbs. | P & C (1992) | ML |
| Dispersal | |||
| Number of mechanisms? | Agricultural produce, animals, machinery, vehicles, garden refuse and contaminated soil. Also insects and water. | P & C (1992) NCC (1992) | MH |
| How far do they disperse? | | | MH |
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