Russian Thistle (Carduus or Silybum)

(Carduus or Silybum)
Musk Thistle, Nodding Thistle, Milk Thistle, St Mary’s Thistle
Silver Milk Thistle, Elephant Thistle or Ivory Thistle

_____RussianThistlePlantMature Russian Thistle Plant and Flower

There are two species of thistles in the genus of the daisy family (Asteraceae). Members of these species grow as annually or as biennial plants with tall up-right stems. the  large waxy leaves are alternate, spine toothed and thorny.  the lower leaves are attached to the stems without petiole while the upper leaves have a clasping base. Thistles tend to have large pink to purple flower heads that are disk shaped at the ends of the stems. Flowers are made up of tubular florets with phyllaries under the flowers occurring in many rows. The outer row has spine-tipped lobes. Compared to other flowering plant generas this species is noted for its disproportionately high number of noxious weeds.

RussianThistledownRussian Thistle Seeds


RussianThistleRussian Thistle Bud


Native to Eurasia and Africa. Others grow else where as escaped introduced species and are extremely invasive plants outside their native range as is the case in Australia and the U.S.

Conditions of Poisoning:
Ingestion, Skin

Toxic Principle:
Potassium nitrate

Clinical Symptoms:
Ingestion: oxygen deprivation

Skin:  allergic reactions from pricks from the thistle spines.


 Lone Star English Setter Club provides this information
as a partial reference of the potential poisons that could harm your dog.
We are not veterinarian’s and DO NOT provide medical help.

If you think that your animal is ill or may have ingested a poisonous substance,
contact your local veterinarian or
the ASPCA’s 24-hour emergency poisoning hotline directly