I’ve been sorting through old photos, and found some of this plant that was growing between the road and a marsh. The photos are from March of last year.
your plant is an immature sweet clover, most likely Melilotus alba if the flowers turn out to be white, or Melilotus officinalis if they were yellow. They are indistinguishable at this stage. It is not a native plant, and it is not restricted to marshes.
Steven Hill, Ph.D., Botanist, SCNPS