Along with briar rose and daffodils, this yellow iris (Flavescens ?) is a common marker of old homestead sites in the NW Arkansas Ozarks. Much like the people who first cultivated it in this part of the world, it's resilient, tough and stubborn. This particular patch covers most of an acre of roadside and forest floor, and seems to be especially well adapted to propagation via county road grader.
The folks at Old House Gardens provide more background on this and several other heirloom varieties at this web site: