Thistles of Nebraska Introduc  on Thistles have long been a concern to agriculture and to the public in general. Canada thistle has been on the Noxious Weed List since 1873.Landowners and homeowners realize this plant was a serious problem and needed to be controlled.ses and Values: Plumeless thistle is an important plant for bu©er‐ﬂies. Its seeds are eaten by numerous species of songbirds. Poisoning: Plumeless thistle may accumulate nitrates, but it is unpal‐atable to livestock. Other: Plumeless thistle is an aggressive weed and is similar to the closely related musk thistle.