Invasiveness Assessment - White arum lily (Zantedeschia aethiopica) in Victoria
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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 White arum lily.
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: White arum lily
Scientific name: Zantedeschia aethiopica
| Question | Comments | Rating | Confidence |
| Establishment | |||
| Germination requirements? | Seeds germinate in late Autumn to Winter and germination is best at temperatures of between 15-20oC (Parsons & Cuthbertson 2001). Requires natural seasonal disturbances for germination. | MH | MH |
| Establishment requirements? | Described as tolerating shade (Blood 2001), so is considered able to establish under a moderate canopy. | MH | MH |
| How much disturbance is required? | Invades dry coastal & riparian vegetation, temporary & permanent freshwater wetlands, warm temperate rainforest (Carr et al 1992). Establishes in relatively intact natural ecosystems. | MH | MH |
| Growth/Competitive | |||
| Life form? | Semi-aquatic: Can grow in water up to 30 cm deep (Burnie et al 1998), occurs in permanent wetlands (Carr et al 1992), swamps, creeks and springs (Keighery 1997). | H | MH |
| Allelopathic properties? | No allelopathic properties were found described in the literature. | L | M |
| Tolerates herb pressure? | ‘Poisonous to stock but rarely touched by animals (Roy et al 1998)’. ‘The plant being very toxic is not grazed by feral or native herbivores once it has become established (Keighery 1997)’. | H | MH |
| Normal growth rate? | ‘Seedling growth is slow at first (Parsons & Cuthbertson 2001)’. However it is also documented that plants from rhizomes grow vigorously (Moore & Hoskins 1997) and that it out competes and completely displaces the native vegetation (Keighery 1997, Weber 2003)’. Moderately rapid growth. | MH | MH |
| Stress tolerance to frost, drought, w/logg, sal. etc? | Re-sprouts following low intensity burns (Wykes 1997). Can tolerate salt, and frost to -10oC for several days a year (Blood 2001), as well as water logging (Moore 1997). Described as drought tender (Bodkin 1990), but, capable of avoiding unfavourable conditions of heat, cold or drought by going dormant (Plummer 1997). Possesses some degree of tolerance to all stresses. | MH | MH |
| Reproduction | |||
| Reproductive system | Reproduces by seed and rhizome proliferation (Parsons & Cuthbertson 2001). | H | MH |
| Number of propagules produced? | ‘Plants produce large numbers of seed (Parsons & Cuthbertson 2001)’. About 40-50 berries per mature spadix are produced, and up to 18 seeds per fruit (Blood 2001). A number of flowering stems are produced on a single plant so it has the potential to produce over 2000 propagules in a season. | H | MH |
| Propagule longevity? | Seeds are short lived with few surviving beyond 4 months (Parsons & Cuthbertson 2001). | L | MH |
| Reproductive period? | Described as forming dense monocultures over large areas on Eclipse and Garden Islands in WA (Wykes 1997, Abbott 1981 in Keighery 1997), which could enable the weed population to be self sustaining. | H | MH |
| Time to reproductive maturity? | Its vegetative reproduction is prolific being able to produce numerous rhizomatous offsets after just 6 months of growth (Plummer 1997, Blood 2001). Offsets survive if removed from the mother plant or if the dominant rhizome is killed (Plummer 1997). Potential for vegetative propagules to become separate individuals in under a year. | H | MH |
| Dispersal | |||
| Number of mechanisms? | Dispersed by birds (Panetta 1988). | H | H |
| How far do they disperse? | As a result of bird dispersal (Panetta 1988), seeds have the potential to travel greater than 1 kilometre. | H | H |
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