The weed is a native of the Mediterranean, Europe and North Africa.
Reason for Introduction
It was introduced as an ornamental garden plant in the 1850s in Victoria, but quickly became naturalised, especially in pastoral regions.
Main Method of Dispersal
The main method of dispersal of Patersonʼs curse is through seed movement in hay and grain, as viable seed in animal faeces, on machinery and vehicles and can also be carried on the coats of native and domestic animals.
Main Method of Reproduction
Reproduction is from seed. Patersonʼs curse is a winter annual or occasionally biennial herb which grows vegetatively as a rosette before producing one or several flowering stems in spring. Most seed germination occurs between mid summer and late autumn, although it may also occur at any other time of the year. Flowering stems are produced in late winter/early spring and flowers and seed are produced from spring to early autumn.
Patersonʼs curse is an erect herb, commonly 60 cm high, but can grow up to 150 cm. Rosettes have green to light-green hairy egg-shaped leaves that may grow to 30 cm long. The rosettes are stalked and have distinct branched veins. Stems are branched, with multiple stems often arising from the plant base. All stems are covered with stiff hairs. Flowers are mostly purple, but white, pink and blue flowering plants are sometimes found. The 2-3 cm long flowers are shaped like curved trumpets with each flower having five stamens, two of which protrude past the end of the flower tube. Flowers generally appear from September to December. Seeds are dark brown to grey and have a roughened seed coat. Up to four seeds develop from each flower. The plant has a stout taproot with numerous lateral roots.
Distribution in the Region
Patersonʼs curse is now widespread in its distribution throughout the ACT. It tends to be more dominant in areas of the ACT where horse agistment enterprises are operating and also in areas where soil disturbance has occurred during construction works on former grazing land.
Invasive Record Elsewhere
Patersonʼs curse also occurs in all states and territories in Australia. The most serious infestations occur in pastoral regions of New South Wales, Victoria, South Australia and in the south-west region of Western Australia.
Patersonʼs curse is toxic to grazing animals. The plant contains pyrrolizidine alkaloids which causes cumulative chronic liver damage, lack of condition and sometimes death. The alkaloid concentration of plants in the rosette stage is twice that of flowering plants. Horses and pigs are highly susceptible, cattle moderately susceptible and sheep and goats less susceptible. Horses and pigs are non-ruminants and do not have the necessary micro-organisms to break down the pyrrolizidine alkaloids.
Patersonʼs curse reduces pasture productivity and can out-compete the more nutritious and palatable pasture plants. The weed can degrade the natural environment and compromise habitat values by crowding out and suppressing native vegetation. It can contaminate hay and grain. It can also affect human health and can result in allergies from pollen and skin irritation from the rough hairy texture of the leaves and stems.
Patersonʼs curse is considered a beneficial plant by some farmers. In the drier regions of southern Australia it is considered the salvation of grazing, thus the name ʻSalvation Janeʼ because it is often the only source of feed (despite being toxic). Patersonʼs curse is also valuable to the honey industry. Whilst flowering, it provides a large amount of pollen necessary to build up bee numbers in a short amount of time and a high level of nectar, which provides an early flow of honey.
Patersonʼs curse needs to be controlled using an integrated approach in order to prevent seed set and reduce the population in the long term. Integrated weed management involves using a number of control methods including the establishment and maintainenance of competitive pastures and crops, the use of a range of selective herbicides, spray grazing using sub-lethal herbicide rates and grazing management, slashing and mechanical/hand removal.
Control in the ACT
Infestations of Patersonʼs curse in the ACT are usually controlled by selective herbicide application, slashing and hand chipping. Whilst cropping and pasture establishment programs offer sound long term benefits, establishment costs can be quite considerable.