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Invasiveness Assessment - Tutsan (Hypericum androsaemum) 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 Tutsan.

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: Tutsan
Scientific name: Hypericum androsaemum

Question
Comments
Reference
Rating
Establishment
Germination requirements?Seeds germinate in autumn.
P & C (1992)
MH
Establishment requirements?Can tolerate shade (moderate canopy) cover.
P & C (1992)
MH
How much disturbance is required?“Establishes in virtually indisturbed bushland”.
P & C (1992)
H
Growth/Competitive
Life form?Erect shrub.

Other.
P & C (1992)
L
Allelopathic properties?None described.
L
Tolerates herb pressure?“Unpalatable and rarely eaten”.
P & C (1992)
MH
Normal growth rate?Whole hillsides may be covered to the exclusion of most other vegetation.

Competes strongly with native species.
P & C (1992)
H
Stress tolerance to frost, drought, w/logg, sal. etc?Tolerant of frost, (occurs in Mansfield, Blue Mountains- Australia: Britain, etc), water logging? (occurs in riparian vegetation).
P & C (1992)
Clapham et al (1952)
Carr et al (1992)
ML
Reproduction
Reproductive systemReproducing by seed.
P & C (1992)
ML
Number of propagules produced?Produce “large numbers “ of seeds. > 20 fruits per plant x 100 seeds - > 2,000 seeds per plant.
P & C (1992)
H
Propagule longevity??
M
Reproductive period?Forms dense monocultures (see P & C 1992 p. 386).

“Widespread, medium to large populations”.
P & C (1992)
Carr et al (1992)
H
Time to reproductive maturity?“Plants do not flower until they are 18 months or two years old”.
P & C (1992)
MH
Dispersal
Number of mechanisms?Small seeds readily contaminate agricultural produce, vehicles, machinery, animals, water and mud. Also bird dispersed.P & C (1992)
H
How far do they disperse?Bird dispersed.
H


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