ARS | Publication request: BULL THISTLE, THE FORGOTTEN INVASIVE RANGE WEED

Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 19, 2003
Publication Date: January 25, 2004
Citation: Young, J.A., Clements, C.D., Harmon, D. 2004. Bull thistle, the forgotten invasive range weed [abstract]. Proceedings of the Society for Range Management, Salt Lake City, Utah, January 24-30, 2004. 57:410.

Technical Abstract: Bull thistle (Cirsium vulgare) is one of the mostly widely distributed exotic species on rangelands. It is usually found in and on the margins of wet meadows and irrigated pastures. On heavily grazed meadows, especially riparian meadows along seasonal water courses, it can be a dominant species. Bull thistle is a biennial species that first forms a leafy rosette that smothers competing vegetation. The second year, multiple flower stalks emerge to a height greater than a meter. Establishment is only from seeds. The lobes of the leaves are spine tipped. The seeds (achenes) are very small (3.5?4.5 mm) and have a persistent pappus 20 to 30 mm long arranged in an flat, stalked umbrella shape. The small seed and large pappus enhance wind dispersal of the mature seeds. Seed and seedbed ecology are critical in the management of this species. Our purpose was to investigate the germination of bull thistle seeds at a wide range of constant or alternating temperatures.