Invasiveness Assessment - Hoary cress (Cardaria draba) 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 Hoary cress.
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: Hoary cress
Scientific name: Cardaria draba
| Question | Comments | Reference | Rating |
| Establishment | |||
| Germination requirements? | Seeds germinate in autumn. | P&C (1992) | MH |
| Establishment requirements? | All the hoary cresses grow under similar open unshaded conditions. | Mulligan & Findlay (1974) | ML |
| How much disturbance is required? | Establish in vigorously growing crops e.g. wheatlands. | Mulligan & Findlay (1974) | MH |
| Growth/Competitive | |||
| Life form? | Erect perennial herb. Geophyte → aerial growth dies in summer with new growth in autumn/spring. | P&C (1992) | ML |
| Allelopathic properties? | Serious effects on wheat & barley. | Qasem (1994) Qasem (1995) | MH |
| Tolerates herb pressure? | Consumed but not always preferred. Capable of rhizome production under moderate herbivory assumed. | McInnis et al (1993) | MH |
| Normal growth rate? | Hoary Cress is a strong competitor in the plant world & being more hardy than most cultivated plants, causes appreciable reduction in yield of both pasture & crops. | Meadly (1965) | H |
| Stress tolerance to frost, drought, w/logg, sal. etc? | Tolerant of fire (heat presumably breaks seed dormancy), waterlogging (occurs along river), drought (occurs on semi arid rangelands). Also tolerates freezing conditions (frost) as occurs in very cold climates such as Finland (Lyons n.d.). | FEIS Hetzel (1985) | MH |
| Reproduction | |||
| Reproductive system | Reproducing from perennial roots & by seed. | P&C (1992) | H |
| Number of propagules produced? | A single plant can produce b/w 1,000-5,000 seeds with a viability of ~80%. | P&C (1992) | H |
| Propagule longevity? | Seed viability rapidly declines with age of seed. 0% seeds germinate after 3 years. | Lyons (n.d) | L |
| Reproductive period? | Forming large patches (monocultures formed). Very dense patches may be found in some areas of Southern Australia. See pic P&C 1992 p.340. | Webb et al (19988) P&C (1992) | H |
| Time to reproductive maturity? | Plants do not usually flower in the first year, assumed to flower in 2nd year. | P&C (1992) | MH |
| Dispersal | |||
| Number of mechanisms? | The main method of dispersal is by movement of pieces of cut root adhering to mud or caught on the lines of cultivation equipment. Seed also dispersed by stock, farm machinery & vehicles, in hay, silage & grain & in water (Anon). | P&C (1992) Anon | MH |
| How far do they disperse? | Many propagules caught in cultivation equip are likely to reach 200-1,000 m. |  | MH |
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