SafePlants

Creeping Thistle and Field Thistle: A Botanical Overview

This section provides information about two closely related thistles: Creeping Thistle (Cirsium arvense) and Field Thistle (Cirsium discolor). While often confused, they are distinct species with overlapping characteristics and distributions.

Considerations for Pets

• Both Creeping and Field Thistles are "prickly" and have "spiny bracts," which could pose a risk of injury to pets if they come into contact with the plants.

Considerations for Children

• Both Creeping and Field Thistles are "prickly" and have "spiny bracts," which could pose a risk of injury to children if they come into contact with the plants.
• Young leaves and stems of Field Thistle are edible after boiling, but care should be taken to correctly identify the plant.

Scientific Names and Common Names

• Creeping Thistle: Cirsium arvense. Also known as Field Thistle, Canada Thistle, Corn Thistle, Perennial Thistle, and Prickly Thistle.
• Field Thistle: Cirsium discolor. Also known as Corn Thistle, Cursed Thistle, Green Thistle, Hard Thistle, and Prickly Thistle.

Taxonomy and Nomenclature

• Family: Asteraceae (also known as Compositae or Daisy Family), subfamily Carduoideae.
• Field Thistle Synonyms: Carduus discolor, Cnicus discolor.
• Creeping Thistle Synonyms: Serratula arvensis L., Cirsium arvense var. horridum Koch.

Distribution and Habitat

• Creeping Thistle: Native to the UK, found in cultivated fields, waste places, hedgerows, and grasslands. Can be found in organic arable fields.
• Field Thistle: Native to North America, widespread and abundant. Found in disturbed areas, usually with damp to wet soils, glades, pastures and abandoned fields, open areas along railroads and roadsides, and waste areas.

Ecological Role

• Creeping Thistle can spread quickly in grassland areas and borders and is difficult to eradicate once established. It is considered a problematic weed.

Morphological Characteristics

• Field Thistle has 1 to 2 inch pink, lavender, or white flower heads with spiny bracts. Plants can reach up to 2 inches across.

Interactions with Other Organisms

• Field Thistle flowers are very attractive to bees and butterflies.
• Field Thistle is attractive to goldfinches.
• Mention is made of field thistle as prey in the text.

Quirky Facts

• The Thistle and Deveron fields are oil fields located northeast of the Shetland Isles and Aberdeen, UK.

Further Information

• USDA, NRCS, Norman A. Berg National Plant Materials Center contributes to information on Field Thistle.
• Discover Life has a page about the biology, natural history, ecology, identification, and distribution of Cirsium discolor (Field thistle).