Le Spotted Knapweed - Paper Courtesy of Le Gigi

Spotted Knapweed – By Gigi Glover

Centaurea maculosa

Quite recently Kelly Omand of the Nantucket Conservation Foundation spotted some Spotted Knapweed growing outside the lab. Spotted Knapweed is an invasive species that originally comes from Eastern Europe, but has been introduced to North America and is now considered an invasive species in much of western America and Canada. Spotted Knapweed is about 2 to 3 inches high, has grayish lance-shaped leaves and thistle-like pink or purple flowers that bloom from July to September. The Spotted Knapweed has become an ecological threat because it takes over dry prairies, oak and pine barrens, and dunes and sandy ridges, the last of which is more relevant to Nantucket. Spotted Knapweed is also poisonous to other plants. Spotted Knapweed is a MDA Prohibited noxious weed in Minnesota. “Prohibited noxious weeds are annual, biennial, or perennial plants that the commissioner designates as having the potential or are known to be detrimental to human or animal health, the environment, public roads, crops, livestock or other property.” – The Minnesota Department of Agriculture. That means that the Minnesota Department of Agriculture thinks that Spotted Knapweed is dangerous to human health, the environment or other important things. Some ways that you can help get rid of Spotted Knapweed are that if you spot it while it is in its early stages you can pull it, you could also mow it so the plants cannot seed, or you could try prescribed burning, but a con of burning is that only extremely hot burns are effective which may also damage some of the native plants which are actually helpful to the environment. A biological way is if you use Seedhead weevils, root-boring weevils, or seedhead flies, as they are commonly used. Thanks to Kelly’s discovery we caught the Spotted Knapweed early and could eliminate it.

Works Cited

Minnesota Department of Agriculture. N.p., n.d. Web. 19 July 2013. <http://www.mda.state.mn.us/plants/badplants/noxiouslist.aspx>.

Minnesota Department of Natural Resources. N.p., n.d. Web. 19 July 2013. <http://www.dnr.state.mn.us/invasives/terrestrialplants/herbaceous/spottedknapweed.html>.

"Spotted Knapweed." Wikipedia. N.p., n.d. Web. 19 July 2013. <http://en.wikipedia.org/wiki/Centaurea_maculosa>.

"Spotted Knapweed." Salt Lake County. N.p., n.d. Web. 19 July 2013. <http://cf9.slco.org/weeds/html/weedinfo/id/spottedKnapweed1.html>.

Le Gigi looking tres chic in her bug resistant chapeau.