Invasiveness Assessment - Galenia (Galenia pubescens) in Victoria

Back | Table | Feedback

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 Galenia.

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)
To view the information PDF requires the use of a PDF reader. This can be installed for free from the Adobe website (external link).

Common Name: Blanket weed
Scientific name: Galenia pubescens

Question	Comments	Rating	Confidence
Establishment
Germination requirements?	Glasshouse trials have shown shoot cuttings can grow at any time of year (Kleinkopf et al, 1976), however, data on seed germination timing is lacking (Detmar 1999). The plant grows in areas with a winter-rainfall regime and in its native range in southern Africa it is absent from summer-rainfall areas (Ross 1994). Possibly the seed responds to seasonal rainfall and spring/summer temperatures, but this is not confirmed. It is a winter-growing perennial (Kleinkopf et al, 1976).	M	L
Establishment requirements?	Noted as occurring in open situations (disturbed coastal situations, roadsides, rock outcrop, etc.). Likely to require direct access to sunlight and rainfall.	ML	H
How much disturbance is required?	Commonly recorded as present on disturbed coastal sites (Marchant et al, 1987), roadsides (Rycroft 1956), and stony flats and rocks (Adamson & Salter 1950). West of Melbourne, Victoria it is recorded on roadsides, floodway, paddocks and nature strips (J. Forrester pers. coms). In New South Wales it is abundant around mining sites (Harden 1990). DSE (2003) record G. pubescens var. pubescens spreading in both disturbed and relatively undisturbed areas in a reserve west of Melbourne, while in Bacchus Marsh – Melton district west of Melbourne it is noted to occur in both woodlands and native grasslands (D’Ombrain & Leversha pers. coms.). For establishment the plant prefers disturbed situations with little or no competition, but evidence in Australia indicates it can also establish in relatively undisturbed areas.	MH	MH
Growth/Competitive
Life form?	Low-growing perennial herb (Kleinkopf et al, 1976). Other.	L	H
Allelopathic properties?	None described. Little is recorded of this plant.	M	L
Tolerates herb pressure?	The plant is known to accumulate high levels of nitrates and oxalates where nitrogen and water are not limited (Williams 1984). However, within its native range (Sth Africa) the plant is used for fodder during periods of drought. In the U.S., one infestation was regularly mown (Ross 1994), but, “continued to flourish.” Anecdotal evidence from Australia is variable; in Victoria it is recorded that cattle do graze it, but rabbits and sheep avoid the plant (J. Forrester pers. coms), but in South Australia sheep readily graze the plant during summer (Honan unpublished). Lazarides et al. (1997) note that G. pubescens is susceptible to grazing, but evidence to support this comment is lacking. Either the plant is not consumed or continues to flourish even if grazed	H	MH
Normal growth rate?	Kleinkopf et al (1976) record that single plant can spread to a diameter of 2 to 3 meters [sic] in a single year. Such growth may exceed that of similar life forms.	H	H
Stress tolerance to frost, drought, w/logg, sal. etc?	Once established it tolerates salt (to seawater concentration under certain conditions) and drought (Kleinkopf et al, 1976). Ross (1994) and Williams (1984) note G. pubescens var. pubescens was tested for fire resistance, however, they offer no information on its tolerance. Additionally, Kleinkopf et al. (1976) comments on its, “potential use as a fire-retardant ground cover. Highly tolerant of two (drought & salinity), possibly tolerant of fire, may be susceptible to frost.	MH	H
Reproduction
Reproductive system	Sexual reproduction. Flowers are perfect, but data is lacking on self- or cross-pollination.	L	L
Number of propagules produced?	Ross (1994) notes that a, “single well-established plant may also produce hundreds (if not thousands) of seeds in a single season.”	M	H
Propagule longevity?	No data	M	L
Reproductive period?	No data. Plant is noted as a perennial species (Kleinkopf et al, 1976, Williams 1984). Plants likely to live beyond two years.	MH	L
Time to reproductive maturity?	No data. The literature suggests that plants flower in the first year.	MH	L
Dispersal
Number of mechanisms?	Given that in areas of low rainfall and poor quality soils, the plant does not produce toxic quantities of nitrates or oxalates (Williams 1984); some animals may consume and spread the seed. This is the likely situation in those areas west of Melbourne where the weed is seen as a serious problem. Honan (unpublished) has observed galahs eating the seed of G. pubescens and suggests other bird species may be implicated in seed dispersal. Forrester (pers. coms) also notes that seed is likely distributed by machinery.	MH	M
How far do they disperse?	Birds and machinery are the most likely long-distance dispersal agents. Propagules easily spread more than one kilometre.	H	M

Feedback

Do you have additional information about this plant that will improve the quality of the assessment?
If so, we would value your contribution. Click on the link to go to the feedback form.

Page top