Teasels

Cut-leaf teasel (Dipsacus laciniatus) was first found in 2005 in Ashland County and is a relatively uncommon invasive species in the NCWMA.  Since there are only five known sites, this species could be eradicated from the area with persistent treatments and vigilance. All known sites in the NCWMA are treated annually.  In order to eradicate this species, it is important to find any other populations. 

Be on the lookout for this species in the coming year and report any occurrences to the NCWMA! Common teasel (Dipsacus follonum) could also potentially be in the area. These species look very similar.  Sometimes teasels are in dried in flower arrangements. The species typically occurs in disturbed openings such as roadsides, but could creep into native openings such as sedge meadows.

Identifying characteristics of both species of teasel: Teasels are biennials with first year plants having  only a basal rosette. Second year plants can be up to seven feet tall with prickly stems. Flower-heads are cylindrical, densely packed, spiny and occur on a long, naked stalks. Stem leaves are opposite and can be up to 12 inches long. 

Cut-leaf teasel (photos): Leaves can be deeply pinnately lobed. Flowers are usually are white. Bracts are shorter than the flower-head.

Common teasel: Leaves are lance-shaped. Flowers tend to be pink to purple.  Bracts are longer than the flower-head.

Source:  Czarapata, Elizabeth. 2005. Invasive Plants of the Upper Midwest. University of Wisconsin Press.  Madison, WI. pp 59-60.

For more information on teasels, visit the DNR's invasives website: Common Teasel

Here is a fact sheet from the Wisconsin UW Extension: Teasel Fact Sheet.