Creeping Water Primrose (Ludwigia grandiflora)

Creeping water primrose (Ludwigia grandiflora) is an emersed aquatic perennial. Native to South America, it was previously named Ludwigia uruguayensis. It grows along the margins of lakes, ponds, and rivers, forming floating mats at first. By summer it becomes slightly woody, forming stalks that will flower above the surface.


Water primrose can be easily spotted due to its bright yellow flowers. There are several varieties of primrose, some are native, and all have similar yellow flowers. Leave appear in two distinct forms. Early in the season, leaves are obovate (rounded) and grow in rosettes (grouped), later in the season the plant will produce lanceolate leaves.


Dense growths of water primrose provide breeding areas for mosquitoes and will degrade both water quality and habitat for fish and wildlife. It fouls intakes used to supply municipal drinking water and irrigation and becomes a navigation hazard. Creeping water primrose should never be introduced to open waters. It has been placed on North Carolina's noxious weed list.


Water primrose was likely brought to the U.S. as an ornamental plant. It produces bright yellow flowers throughout much of the season. It ranges from New York to Florida, west to Texas, and along the west coast. Primrose produces abundant seeds that are very small. It will also reproduce by fragmentation; roots will readily grow from the nodes.


Control methods are limited to herbicide use. No biological control agents have been found. Mechanical removal (except hand-removal of small infestations) is difficult and costly