General poisoning notes:

Common milkweed (Asclepias syriaca) is a native perennial herb found in eastern Canada in fields, ditches, and waste places. This plant has poisoned sheep in the eastern United States. The plant contains cardiac glycosides, which are toxic to animals (Reynard and Norton, Joubert 1989).

References:

Joubert, J. P. 1989. Cardiac glycosides. Pages 61-97 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. II. Glycosides. CRC Press, Inc., Boca Raton, Fla., USA. 277 pp.

Reynard, G. B., Norton, J. B. 1942. Poisonous plants of Maryland in relation to livestock. Univ. MD. Agric. Exp. Stn. Bull., A10. 312 pp.

Nomenclature:

Scientific Name: Asclepias syriaca L.

Vernacular name(s): common milkweed

Scientific family name: Asclepiadaceae

Vernacular family name: milkweed

References:

Agriculture Quebec. 1975. Noms des maladies des plantes du Canada/ Names of plant diseases in Canada. , Quebec City, Que., Canada. 288 pp.

Alex, J. F., Cayouette, R., Mulligan, G. A. 1980. Common and botanical names of weeds in Canada/Noms populaire et scientifiques des plantes nuisibles du Canada. Revised. Agric. Can. Publ., Ottawa, Ont., Canada. 132 pp.

Bailey, L. H., Bailey, E. Z. 1976. Hortus third. Revised. MacMillan, New York, N.Y., USA. 1290 pp.

Scoggan, H. J. 1978, 1979. The flora of Canada. Nat. Mus. Nat. Sci. (Ottawa) Publ. Bot. 7(1)-7(4). 1711 pp.

Van Wijk, H. L. 1911. A dictionary of plant names. Martinus Nijhoff, The Hague, The Netherlands. 1444 pp.

Victorin, M. 1964. Flore Laurentienne. 2nd ed. Univ. Montreal, Montreal, Que., Canada. 952 pp.

Geographic Information

Manitoba
New Brunswick
Nova Scotia
Ontario
Prince Edward Island
Quebec

References:

Bailey, L. H., Bailey, E. Z. 1976. Hortus third. Revised. MacMillan, New York, N.Y., USA. 1290 pp.

Boivin, B. 1966, 1967. Énumération des plantes du Canada. Provencheria 6. Nat. Can. (Que.) 93: 253-274; 371-437; 583-646; 989-1063. 94: 131-157; 471-528; 625-655.

Toxic parts:

latex
leaves
stems

References:

Joubert, J. P. 1989. Cardiac glycosides. Pages 61-97 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. II. Glycosides. CRC Press, Inc., Boca Raton, Fla., USA. 277 pp.

Toxic plant chemicals:

desglucosyrioside
syrioboside
syrioside

References:

Joubert, J. P. 1989. Cardiac glycosides. Pages 61-97 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. II. Glycosides. CRC Press, Inc., Boca Raton, Fla., USA. 277 pp.

Animals/Human Poisoning:

Note: When an animal is listed without additional information, the literature (as of 1993) contained no detailed explanation.

Sheep

General symptoms of poisoning:

death

Notes on poisoning:

A dozen sheep died after ingesting large amounts of common milkweed in Maryland. The plants, which were almost the only vegetation available during a drought, are normally distasteful to livestock (Reynard and Norton 1942).

References:

Reynard, G. B., Norton, J. B. 1942. Poisonous plants of Maryland in relation to livestock. Univ. MD. Agric. Exp. Stn. Bull., A10. 312 pp.

Information Source: ©Canadian Poisonous Plants Information System, Canadian Biodiversity Information Facility.