Echium plantagineum L.: Paterson’s curse

California Pest Rating for
Echium plantagineum L.:  Paterson’s curse
Lamiales: Boraginaceae
Pest Rating: A  |  Proposed Seed Rating: P


Initiating Event:

This plant has been detected spreading in Sonoma County, California.

History & Status:

Paterson’s curse is a softly hairy, winter annual that produces a branched inflorescence of the “fiddleneck” type. The showy, bell-shaped flowers are usually purple but also blue or pink with 2 of the 4 stamens emerging from the corolla tube. Each flower produces 4 small nutlets. Paterson’s curse is an attractive plant and has been included in “wildflower” mixes on occasion. In Australia it has served as a rangeland plant in dry areas, but its use for livestock is risky (see below). Because of its toxicity to livestock, Paterson’s curse has been listed as a noxious weed by the state of Oregon.

Official Control: Paterson’s curse has never been seen as a potential problem in California, as it has not been detected as spreading from introduction sites until now. It has never been subject to official control.

California Distribution:  Paterson’s curse is reported from San Diego, Marin (historic) and Sonoma Counties

California Interceptions: Vouchered specimens are known from San Diego and Marin Counties.

United States: Paterson’s curse is known also from a limited area of Oregon

International: Paterson’s curse is native to the western Mediterranean. It is reported as naturalized and a serious environmental and rangeland weed in Australia, Eastern Europe, the Near East, and Southern South America. It is occasional in New Zealand.

The risk Paterson’s curse would pose to California is evaluated below.

Consequences of Introduction: 

1)  Climate/Host Interaction: The plant has adapted to a wide area in its native range and is highly invasive in areas of Australia ecologically similar to California. Therefore Paterson’s curse receives a High (3) in this category.

Evaluate if the pest would have suitable hosts and climate to establish in California.  Score:

Low (1) Not likely to establish in California; or likely to establish in very limited areas.
– Medium (2) may be able to establish in a larger but limited part of California.
High (3) likely to establish a widespread distribution in California.

 2)  Host Range: Risk is High (3) as weeds do not require any one host, but grow wherever ecological conditions are favorable.

Evaluate the host range of the pest. Score:

Low (1) has a very limited host range.
– Medium (2) has a moderate host range.
High (3) has a wide host range.

3)  Pest Dispersal Potential: Paterson’s curse produces via numerous seeds and spreads rather slowly. The seed bank is moderately persistent. Once established, Paterson’s curse is hard to eradicate. Paterson’s curse receives a Medium (2) in this category.

Evaluate the natural and artificial dispersal potential of the pest. Score:

Low (1) does not have high reproductive or dispersal potential.
– Medium (2) has either high reproductive or dispersal potential.
High (3) has both high reproduction and dispersal potential.

4)  Economic Impact: Young growth is readily eaten and provides considerable sustenance to stock, whilst older growth is rough and hairy and generally avoided by stock. The hairiness can cause slavering, dermatitis, inflammation and itching to animals and man. Paterson’s curse contains toxins that cause cumulative chronic liver damage and animal mortality, especially if substantial amounts of herbage are eaten over prolonged periods. Horses are the most susceptible of common livestock. Paterson’s curse is considered the primary cause of pyrrolizidine alkaloid poisoning in horses in Australia and toxicity in cattle in Brazil. Paterson’s curse is also the major cause of sheep deaths from primary pyrrolizidine alkaloid poisoning in New South Wales. Paterson’s curse replaces superior range species and can significantly reduce row crop production under certain regimes (e.g., no till cultivation). Paterson’s curse receives a High (3) in this category.

Evaluate the economic impact of the pest to California using the criteria below. Score:

A.  The pest could lower crop yield.
B.  The pest could lower crop value (includes increasing crop production costs).
C.  The pest could trigger the loss of markets (includes quarantines).
D.  The pest could negatively change normal cultural practices.
E.  The pest can vector, or is vectored, by another pestiferous organism.
F.  The organism is injurious or poisonous to agriculturally important animals.
G.  The organism can interfere with the delivery or supply of water for agricultural uses.

Low (1) causes 0 or 1 of these impacts.
Medium (2) causes 2 of these impacts.
High (3) causes 3 or more of these impacts.

5)  Environmental Impact: Paterson’s curse is likely to trigger new chemical treatments by ranchers and land managers. The plant can dominate grasslands and roadsides, excluding native plants and lowering biodiversity. Rare taxa that might be affected include grassland species such as showy Indian clover (Trifolium amoenum) and CA filaree (California macrophylla), vernal pool species such as Burke’s goldfields (Lasthenia burkei) and CA tiger salamander (Ambystoma californiense), and grazers such as tule elk (Cervus canadensis nannodes). The plant can disrupt natural communities. Paterson’s curse receives a High (3) in this category.

Evaluate the environmental impact of the pest on California using the criteria below.

A.  The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.
B.  The pest could directly affect threatened or endangered species.
C.  The pest could impact threatened or endangered species by disrupting critical habitats.
D.  The pest could trigger additional official or private treatment programs.
E.  The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

Score the pest for Environmental Impact. Score:

Low (1) causes none of the above to occur.
Medium (2) causes one of the above to occur.
High (3) causes two or more of the above to occur.

Consequences of Introduction to California for Paterson’s curse: High (14)

Add up the total score and include it here.

Low = 5-8 points
Medium = 9-12 points
High = 13-15 points

6)  Post Entry Distribution and Survey Information: Paterson’s curse has been found in in 2-3 counties in California, but may still be eradicated. It receives a Low (-1) in this category.

Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included.

Not established (0) Pest never detected in California, or known only from incursions.
-Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).
Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.
High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

 Final Score:

The final score is the consequences of introduction score minus the post entry distribution and survey information score: High (13)


Paterson’s curse has been in California a long time, but has not spread widely. Its behavior in Australia and the site in Sonoma suggest that it is just beginning its spread here in California.

Conclusion and Rating Justification:

A very bad weed. Deserves an A rating as known populations are limited. Chances of state eradication are high.


Baldwin, B. G., D. H. Goldman, D. J. Keil, R. Patterson, T. J. Rosatti, and D. H. Wilken, editors. 2012. The Jepson manual: vascular plants of California, second edition. University of California Press, Berkeley.

Consortium of California Herbaria (

Culvenor C. C. J., M. V. Jago, J. E. Peterson, L. W. Smith, A. L. Payne, D. G. Campbell, J. A. Edgar & J. L. Frahn. 1984. Toxicity of Echium plantagineum (Paterson’s Curse). 1. Marginal toxic effects in Merino wethers from long-term feeding. Australian Journal of Agricultural Research, 35: 293-304.

Culvenor C. C. J, 1956. The alkaloids of Echium plantagineum L. I. Echiumine and Echimidine. Australian Journal of Chemistry 9: 512-520.

Dellow J.J., & J. T. Seaman. 1985. Distribution of Echium plantagineum L. and its association with pyrrolizidine alkaloid poisoning in horses in New South Wales. Plant Protection Quarterly 1: 79-83.

Flora of North America Editorial Committee, eds.  1993+.  Flora of North America North of Mexico.  16+ vols.  New York and Oxford.

Invasive Species Compendium. Echium plantagineum. Accessed 2/10/2015:

Kozuharov, S. . 1972. Echium in Flora Europaea Vol. 3: Diapensiaceae to Myoporaceae. T. G. Tutin, V. H. Heywood, N. A. Burges, D. H. Valentine, S. M. Walters & D. A. Webb, eds. Cambridge University Press. United Kingdom.

Seaman JT, 1987. Pyrrolizidine alkaloid poisoning of sheep in New South Wales. Australian Veterinary Journal, 64: 164-167.

Schild A. L., A. C. Motta, C. F. Riet Correa, F. C. Karam & F. B. Grecco. 2004. Photosensitization in cattle in Southern Brazil. In: Acamovic T, Stewart CS, Pennycott TW, eds. Poisonous Plants and Related Toxins. Wallingford, UK: CABI Publishing: 62-166.

Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 654-0312;[@]

Comment Period:  CLOSED

The 45-day comment period opened on Tuesday,  April 7, 2015 and closed on May 22, 2015.

Pest Rating: A  |  Proposed Seed Rating: P

Posted by ls