Thats definitely Crimson clover.

Its an annual that must reseed itself to come back the next year. In the northeast - you need to treat it like an annual - that never comes back though - its more suited for the South.

I have a plot that had a Crimson Clover percentage - and this is my third year- I still had the red heads pop up this year - but less each year. Some "blends" have crimson clover as a component because it establishes quickly (compared to white clovers).

FH