Most water primroses are emersed plants; however, Ludwigia repens is mostly submersed and does not look much like the other Ludwigias. There are many species, some large and shrubby, and some small and floating. They commonly grow in shallow marshy areas, borrow pits and ditches. They flower in all seasons except winter. There are 30 species of Ludwigia occurring in Florida (Wunderlin, 2003). Water primroses are scattered throughout the US (Kartesz, 1999).
Water primroses grow to five or six feet tall; however some are only inches tall. Stems are branched and sometimes have long hairs. The leaves are ovate to lance-shaped, and up to six inches long. Leaves are covered on both sides by minute soft hairs. Most water primroses have conspicuous yellow flowers. The flowers have four or five petals.
For brief control information, see Efficacy of Herbicide Active Ingredients Against Aquatic Weeds by K. Langeland, M. Netherland, and W. Haller.