Peduncles sessile-glandular. Phyllaries usually sessile-gland-ular, rarely tomentose, the longer 10-15 mm. 2n = 36. Flowering Jul-Sep. Mostly wet, disturbed sites, oil-seed or irrigated crops, roadside ditches, along streams, wetlands; 0-2200. m; introduced; Alta., B.C., Man., N.B., N.S., Ont., P.E.I., Que., Sask., Yukon; Calif., Colo., Conn., Del., Idaho, Ill., Ind., Iowa, Kans., Maine, Md., Mass., Mich., Minn., Miss., Mont., Nebr., Nev., N.J., N.Y., N.C., N.Dak., Ohio, Oreg., Pa., S.Dak., Tenn., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; Europe; widely introduced elsewhere. Subspecies uliginosus is considered a noxious weed in Alaska, Idaho, Illinois, Iowa, Maryland, Minnesota, North Carolina, North Dakota, South Dakota, and Wyoming.
From Flora of Indiana (1940) by Charles C. Deam
As shown by the map this form of the sow thistle is becoming well established in the state. Most of my specimens are from highways and usually the colony is near a dwelling. This variety is ornamental when in flower and while I do not know that it has been used as a garden plant, I strongly suspect it has, because of the proximity of most of the colonies to habitations. Obviously its principal mode of propagation is by the multiplication of rhizomes since the colonies noted are closed and few separate plants observed. Special stress should be placed upon the eradication of the few colonies we now have, or in due time this weed will be ubiquitous in the state. In nearly every instance where I have found it I have informed the owner of the land of the dangerous character of the plant, and I have also notified the county agricultural agent of its existence. I have no data concerning the general distribution of the variety.
……
Indiana Coefficient of Conservatism: C = null, non-native
