Echium plantagineum (Purple Viper's Bugloss) is a species of Echium, native to western and southern Europe (from southern England south to Iberia and east to the Crimea), northern Africa, and southwestern Asia (east to Georgia).
It is an annual or biennial plant growing to 20-60 cm tall, with rough, hairy, lanceolate leaves up to 14 cm long. The flowers are purple, 15-20 mm long, with all the stamens protruding, and borne on a branched spike.
The name Salvation Jane comes from South Australia. In times of drought, many of the states grazing pastures died. Due to its drought hardiness, Echium was a source of food to the grazing animals in the state, hence the name Salvation Jane.
In the 1880s it was introduced to Australia, probably both as an accidental contaminate of pasture seed and as an ornamental plant. It is said that both names for the plant derive from Jane Paterson or Patterson, an early settler of the country near Albury. She brought the first seeds from Europe to beautify a garden, and then could only watch helplessly as the weed infested previously productive pastures for many miles around.
Patterson's Curse is now a dominant pasture weed through much of New South Wales, the Australian Capital Territory, Victoria, South Australia and Tasmania and also infests native grasslands, heathlands and woodlands. The plants contain pyrrolizidine alkaloids and, when eaten in large quantities, cause reduced livestock weight or even (in severe cases) death. Paterson's Curse can kill horses and irritate the udders of dairy cows and the skin of humans. After the 2003 Canberra bushfires over 40 horses were officially put down after eating the weed.
Patterson's Curse has positive uses — it is the source for a particularly fine grade of honey (although some say that Patterson's Curse honey may be poisonous, especially after drought) and, with proper handling, is used for cattle (though not sheep) feed in northern South Australia. However, the annual cost in control measures and lost production was estimated (in a 1985 study by the Industries Assistance Commission) to be over $30 million, compared to $2 million per year in benefits.
The plant has hairy, dark green, broadly oval rosette leaves to 30cm long. The several seeding stems grow to 120cm in height and develop branches with age. Flowers develop in clusters; they are purple, tubular and 2-3 cm long with 5 petals. It has a fleshy taproot with smaller laterals.
Although generally a spring-flowering annual, Patterson's Curse is highly adaptable and, given suitable rainfall, some plants germinate out-of-season and endure for longer than one year. It is a very prolific seed producer; heavy infestations can yield up to 30,000 seeds per square metre. Patterson's Curse can germinate under a wide variety of temperature conditions, tolerates dry periods well and responds vigorously to fertiliser. If cut by a lawnmower, it quickly recovers and sends out new shoots and flowers.
The plant disperses by movement of seeds — on the wool or fur of animals, the alimentary tracts of grazing animals or birds, movement in water and most importantly as a contaminant of hay or grain. This is most noticeable in times of drought, when there is considerable movement of fodder and livestock.
It can rapidly establish a large population on disturbed ground and competes vigorously with both smaller plants and the seedlings of regenerating overstorey species. Its spread has been greatly aided by human-induced habitat degradation, particularly the removal of perennial grasses through overgrazing by sheep and cattle and the introduction of the rabbit. Patterson's Curse is rarely able to establish itself in habitats where the native vegetation is healthy and undisturbed.
Control of the plant is carried out by hand (for small infestations) or with any of a variety of herbicides, and must be continued over many years to reduce the seedbank. (Most seeds germinate in the first year, but some survive for as long as five years before germinating.) In the longer term, perennial grasses (which do not need to regenerate from seed each year) can out-compete Patterson's Curse, and any increase in perennial cover produces a direct decrease in Patterson's Curse.
The Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) has investigated numerous biological control measures, and of the 100-odd insects found feeding on Patterson's Curse in the Mediterranean, judged six safe to release in Australia without endangering crops or native plants. The weevils Mogulones larvatus and Mogulones geographicus and the flea beetle Longitarsus echii are currently in use by the New South Wales Department of Agriculture. While the CSIRO is modestly optimistic, it is expected that biological control measures, if they are successful at all, will take decades to be effective.
Three other Echium species have been introduced and are of concern; Viper's Bugloss (Echium vulgare) is the most common of them. Viper's Bugloss is biennial, with a single unbranched flowering stem and smaller, more blue flowers, but is otherwise similar. This species is also useful for honey production.