Invasiveness Assessment - Hemlock (Conium maculatum) 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 Hemlock.
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: Hemlock
Scientific name: Conium maculatum
| Question | Comments | Reference | Rating |
| Establishment | |||
| Germination requirements? | Seeds mostly germinate in autumn, but sometimes in spring. | P & C (1992) | MH |
| Establishment requirements? | Occurs in ‘shady’ habitats. | Robbins et al (1951) P & C (1992) | MH |
| How much disturbance is required? | Occurs in minor disturbed natural ecosystems, e.g. grassland, grassy woodland, riparian vegetation, warm temperate rainforest. | Carr et al (1992) | MH |
| Growth/Competitive | |||
| Life form? | Erect annual or biennial herb. Other. | P & C (1992) | L |
| Allelopathic properties? | None described. |  | L |
| Tolerates herb pressure? | When green, it is rarely eaten by cattle and sheep, probably because of its offensive odour. | P & C (1992) | MH |
| Normal growth rate? | Can preclude most other vegetation. Is capable of rapid establishment after autumn rains. | P & C (1992) | H |
| Stress tolerance to frost, drought, w/logg, sal. etc? | Tolerance to water logging (occurs on riverbeds), assumably also frost (occurs in southern Tasmania and Canada). Rutledge & Gupta (1996) | Webb et al (1998) P & C (1992) | ML |
| Reproduction | |||
| Reproductive system | Reproducing by seed. | P & C (1992) | ML/ |
| Number of propagules produced? | (Estimated using pictures in Kleinschmidt & Johnson (1977) & US Department of Agriculture (1976). 30 inflorescence x 10 umbels/inflorescence x 10 florets/umbel x 1 seed/floret = 3,000 seeds per plant. | | H |
| Propagule longevity? | Seeds are believed to be short-lived in the soil. | P & C (1992) | L |
| Reproductive period? | Forms dense infestations. See pic. P & C (1992) p. 168 | P & C (1992) | H |
| Time to reproductive maturity? | Some plants produce flowering stems in the first spring. | P & C (1992) | H |
| Dispersal | |||
| Number of mechanisms? | Machinery, vehicles, agricultural produce, mud and clothing. Also water, wind, gravel and soil. Annuals (e.g. stock & dogs). | P & C (1992) Blood (nd) | MH |
| How far do they disperse? | As occurs near waterways, some seeds likely will disperse > 200 m especially in floodwaters. Most more likely to disperse < 200 m. | See Kleinschmidt & Johnson (1977) | ML |
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