Paterson's Curse

Named for the property from which it spread in the 1880's Paterson's curse (PC) is an erect, purple flowered, annual weed of roadsides, degraded farmland, and disturbed land.

Seeds are spread by machinery, infected garden refuse and soil as well as water runoff.

Germination generally occurs from autumn to winter and purple flowers form from spring to summer, though in some areas the plants normal life cycle has become variable.

Paterson's curse contains alkaloids that build up in the livers of livestock and can be toxic, causing death. Pigs and horses are more sensitive followed by cattle, sheep and goats.

Manual removal can be effective if the taproot is removed intact.

Management calendar

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Control options


Due to legal requirements the PHBG does not recommend specific herbicides.

Please follow the links below to specific chemical control options for Paterson's curse.


Isolated plants can be removed manually making sure that the majority of the taproot is also removed.

If the plant is flowering or seeding it should be burnt to reduce spread.

Wethers and rams can be used to heavily graze the weed over spring to reduce seed production.


There are several bio control agents that have been released to help reduce the competitiveness of Paterson's curse.

  • Leaf mining moth (Dialectica scalariella)

  • Leaf eating weevil (Ceutorhynchus larvatus)

  • Stem boring beetle (Phytoecia coerulescens)

  • Two flea beetles (Longitarsus aeneus and L. echii)

The Paterson's Curse Crown Weevil has taken 12 years to establish in sufficient numbers to reduce the size, vigour and density of Paterson's Curse.

At present biocontrol agents are providing varying degrees of control with the Crown Borer causing the most damage.

The Heliotrope moth (Utetheisa pulchelloides) is a white spotted moth and often seen in Heliotrope and Paterson's Curse infestations. The caterpillars have sparse grey hairs, and are black with orange spots and broken cream lines along the body.