I don't know why this plant is often Greek valerian when it's relatives are mostly Jacob's-ladders. This one is sometimes called that, most often spreading or creeping Jacob's-ladder. I do know that it is rare in Michigan, only occurring in seven southern counties. I could even tell you which counties, how many times it has been reported, and the most recent years. This info is available on line at Michigan Natural Features Inventory. Attached to Michigan State University, they do a terrific job exploring and recording our at-risk flora and fauna. They have survived vigorous political attacks, threats of defunding, and real world issues like photographers that don't report sightings. The site would tell you that this was last seen in Lenawee in 1999. Many states, particularly the more progressive, have offices similar to this. Species are also tracked at the national level by the USDA. As a result, we know quite a bit about our at risk species. Drives developers crazy! Greek valerian grows in woods, often near streams, in AL, AR, CT, DE, GA,IL, IN, KS, KY, MA, MD, MI(T), MN, MO, MS, NC, NH, NJ(E), NY, OH, OK, PA, RI, SD, TN, VA, VT, WI, WV, ON, and QC. Lenawee Co MI, 5/13/14.