We asked one of our experts at the Meadowlands Commission, Dr. Ross Feltes, and he identified it as saltmarsh fleabane — a.k.a. sweetscent or Pluchea odorata.
Feltes, a naturalist, reports that "it commonly colonizes disturbed brackish wetlands."
He adds: "In past years it has grown on top of the cedar stumps in the impoundments at Mill Creek Marsh, making for an unusual, but pretty, feature."
We saw it there this week (below).