Rattail fescue is a common non-native annual grass throughout lower and mid-elevations in the Boise Front.  Although usually not as aggressive or conspicuous as better-known invasive grasses such as cheatgrass (Bromus tectorum), feral rye (Secale cereale), and South African wiregrass (Ventenata dubia), it nevertheless competes with native species for diminishing habitat.  This includes not only native wildflowers, but also a couple of other species of Vulpia that are native locally:  small fescue (Vulpia microstachys) and six-weeks fescue (Vulpia octoflora).  All of these species of Vulpia are alternatively treated as annual members of a broadly circumscribed Festuca.

Diagnostic characters of rattail fescue include narrow inflorescences and mismatched glumes (the paired bracts at the base of each spikelet), with one glume being less than half the length of the other glume.