Foxtail

Green foxtail (Setaria viridis) is a summer annual grassy weed identifiable by its distinctive fuzzy, cylindrical seed head that resembles a fox tail. It germinates in late spring as soil temperatures warm and dies with the first frost in fall.

Foxtail is a monocot — same grass family as your fescue — which means post-emergent selective control is limited. Like goosegrass and crabgrass, the chemistry cannot easily distinguish between the weed and the desirable grass. Pre-emergent herbicide applied before March 15th is the primary defense. Prodiamine or dithiopyr (Dimension) applied on time prevents germination entirely.

On a well-maintained lawn care program with properly timed pre-emergent, foxtail is a non-issue. You see it primarily in lawns with no pre-emergent program, in areas where the pre-emergent barrier was broken by aeration or soil disturbance after application, or along hardscape edges where soil conditions are harsh enough that fescue has thinned and foxtail fills the competitive gap.

Foxtail is not one of the difficult weeds in Middle Tennessee. It is an annual controlled by the same pre-emergent timing that handles crabgrass, goosegrass, and spurge. If you are seeing foxtail in your lawn, the issue is almost always a pre-emergent timing problem rather than a foxtail-specific control challenge.