Cirsium discolor (Field Thistle)

Plant Info
Also known as: Pasture Thistle
Genus:Cirsium
Family:Asteraceae (Aster)
Life cycle:biennial
Origin:native
Habitat:sun; fields, along roads, open woods
Bloom season:July - October
Plant height:3 to 7 feet
Wetland Indicator Status:GP: FACU MW: FACU NCNE: UPL
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

Pick an image for a larger view. See the glossary for icon descriptions.

Detailed Information

Flower: Flower shape: indistinct Cluster type: panicle

[photo of flowers] Flower head is 1½ to 2 inches across, pink to lavender, or occasionally white. Several to many flower heads branch off the main stem in the upper part of the plant.  The bracts are flat, green with a white stripe and resemble fish scales. Each bract has a ¼ inch long needle-like spine at the tip that sticks straight out.

Leaves and stem: Leaf attachment: alternate Leaf type: lobed Leaf type: simple

[photo of leaves] Leaves are up to 9 inches long and 3 inches wide, divided into several narrow lobes, some divided further, with small spines all along the edges and longer spines at the lobe tips.

[photo of leaf underside] The underside of leaves is white, covered in short hairs. Stems are also covered in hairs, but are not spiny, and often heavily branched in the upper plant.

Notes:

Field Thistle most closely resembles Tall Thistle (Cirsium altissimum), which also has soft needle-like spines on the floral bracts, hairy stems and white on the underside of leaves. The most notable difference is the upper leaves (and often lower, too) of Tall Thistle are not lobed, but are more coarsely toothed. The non-native thistles are distinguished by their sharp spines, especially along the stems. While most references give a height of Field Thistle up to 7 feet, we've seen plants rather taller.

Please visit our sponsors

  • Minnesota Native Plant Society

Where to buy native seed and plants ↓

Map of native plant purveyors in the upper midwest

  • Natural Shore Technologies - Using science to improve land and water
  • Itasca Ladyslipper Farm - Native orchids, container grown
  • Prairie Restorations - Bringing people together with the land
  • Shop for native seeds and plants at PrairieMoon.com!
  • Shooting Star Native Seeds - Native Prairie Grass and Wildflower Seeds

More photos

Photos by K. Chayka taken at Long Lake and Rice Creek Regional Parks, Ramsey County. Other photos courtesy Peter M. Dziuk.

Comments

Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Glen - Burnsville
on: 2014-07-03 03:08:14

It cropped up on the edge of our lawn near some shrubs in an area that in the past was mowed but I've decided to let grow mostly wild now. I already thought that this thistle looked cool and was inclined to leave it be and knowing now that it is native I'm even more inclined to just let it grow. It is now early July and no flowers have shown up yet so I have its blooming to look forward to also.

Posted by: Gary W - Skelton and Atkinson townships in Carlton County
on: 2017-07-03 15:35:56

This plant grows in a few spots just off the Munger Trail near HWY 61 in Atkinson Township. It was there long before the old RR grade was turned into a trail. And today, I found a plant in bud growing in an old field behind my house. Not 100% positive on that one's id but in a week or so it should be in flower. Everything else points to C. discolor, though.

Post a comment

Note: All comments are moderated before posting to keep the riff-raff out. An email address is required, but will not be posted—it will only be used for information exchange between the 2 of us (if needed) and will never be given to a 3rd party without your express permission.

For info on subjects other than plant identification (gardening, invasive species control, edible plants, etc.), please check the links and invasive species pages for additional resources.



(required)




Note: Comments or information about plants outside of Minnesota and neighboring states may not be posted because Id like to keep the focus of this web site centered on Minnesota. Thanks for your understanding.