The scientific name for the Nyjer plant is Guizotia abyssinica. Its bloom has yellow, daisy-like flowers, and before it is shipped into the country the Nyjer seed has been heat treated to prevent the growth of any noxious seeds. Even if it did sprout, Michigan’s growing season is too short to produce a flowering plant.
There are 20 different kinds of native thistle plants in the U.S. that are also adored by finches, but the most common thistle that pops up in people’s yards was actually brought over from Europe. Canada thistle, Cirsium arvense, is a vigorous, competitive weed that occurs in a wide range of habitats and is difficult to control due to its ability to re-grow from its extensive, deep creeping root system.
Image by RunnerJenny via FlickrIt is native to Europe and was apparently introduced to North America by colonists in the early 17th century. It is illegal to sell and by 1991 it had been declared noxious by at least 35 states and 6 Canadian provinces. Canada thistle is a 2 to 5 foot tall herbaceous perennial with numerous small, compact purple or white flowers on the upper stems from June to Oct.