Weed Seed: Echium plantagineum (Paterson's curse)

Invasive Plant - Paterson's curse (Echium plantagineum)

Family

Boraginaceae

Common name

Paterson's curse

Regulation

Prohibited Noxious, Class 1 in the Canadian Weed Seeds Order, 2016 under the Seeds Act. All imported and domestic seed must be free of Prohibited Noxious weed seeds.

Listed on the List of Pests Regulated by Canada established under the Plant Protection Act.

Distribution

Canadian: There have been several records from Canada but it has not persisted (CFIA 2014^Footnote 1).

Worldwide: Broad Mediterranean native distribution. Introduced to Australia, South Africa, southern South America, and the western United States (CFIA 2014^Footnote 1).

Duration of life cycle

Winter annual or biennial

Seed or fruit type

Nutlet

Identification features

Size

• Nutlet length: 2.5 - 4.2 mm
• Nutlet width: 1.5 - 3.0 mm

Shape

• Ovate-shaped nutlet with a flat base and narrow top; slightly trigonous

Surface texture

• Nutlet is densely covered in small tubercles and ridges

Colour

• Colour of nutlet is off-white to straw-yellow, surface between the tubercles is pale

Other structures

• Nutlet has a flat base and a pronounced ridge around the centre of the fruit.

Habitat and crop association

Pastures, roadsides and disturbed areas (CFIA 2012^Footnote 2). Carries over as a weed in crops when pastures are rotated with cereals or other crops (CABI 2016^Footnote 3).

General information

Paterson's curse was introduced into Australia in the 1880s, where it proved to be an aggressive, drought-tolerant, herbicide-resistant and toxic weed (Kloot 1982^Footnote 4). The plants contain toxic chemicals that can cause liver damage in pigs and horses (Culvenor 1956^Footnote 5).

Similar species

Blueweed (Echium vulgare)

• The two species are similar in size, ovate shape, straw-yellow colour and surface ornamentation.
• Blueweed nutlets are a darker colour than Paterson's curse, and the surface ornamentation is usually low ridges and streaks rather than tubercles.
• The surface colour of blueweed (between the tubercles) is dark brown or black, the surface colour of Paterson's curse is pale.

Photos

Similar species