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Protecting Northern Michigan's ​Water Resources


Invasive water-primrose species are aquatic plants that can thrive and spread in shallow water areas including wetlands and shorelines. Water-primrose can grow quickly, with both upright stems and horizontal runners crowding out important native vegetation.

Scientific Name:

Ludwigia grandifolia, Ludwigia peploides and Ludwigia hexapetala

Other common names: Primrose willow, floating primrose willow, creeping water primrose


What to look for

  • Water-primrose may be floating in the water or emergent along the water’s edge.
  • Showy yellow flowers with 5 or 6 petals.
  • Upright growth up to 2 ft. and can also spread horizontally. Stems are reddish in color.
  • Leaves are dark green in color, elongated, and may be lanceolate (willow-like) or oblanceolate (spatula-like) in shape.
  • Water-primrose is an aggressive species and can form dense mats along waterways.


Species info


Water-primrose thrives in emergent marshes and wetlands with periodic flooding, along shorelines and in water along the shoreline. Plants can survive in water up to 3 meters in depth but tends to prefer shallower water habitats near the shoreline.


Native: The native range of water-primrose species is highly debated, spanning areas of North, Central, and South America. In the U.S., water-primrose is native to Southeastern states.

U.S. Distribution: Water-primrose has been reported across the East Coast from Massachusetts to Florida, from the Gulf Coast north to Missouri, and along the West Coast from southern California to Seattle. 

In Michigan: Water-primrose was first detected in 2018 in Detroit International Wildlife Refuge in Wayne County. Populations have been verified in Wayne, Monroe, Macomb, and Ottawa counties. 

Local concern

Water-primrose is aggressive and can spread quickly through aquatic habitats, displacing other wetland plants. 

How it spreads

Water-primrose has been introduced as ornamental landscape plantings.


Herbicide has been shown to be an effective control option if populations are detected at an early stage.

Common look-alikes

Before reporting invasive water-primrose, review these native ludwigia species that can be mistaken for invasive water primrose. Note that native ludwigia plants have flowers with four petals and/or four sepals. Click on each photo for descriptions.

Invasive water-primrose species have showy yellow flowers with five petals. Photo by Rebekah D. Wallace, University of Georgia, Bugwood.org
The flower, leaves and runners of Ludwigia peploides, another of the invasive water-primroses. Photo by Graves Lovell, Alabama Department of Conservation and Natural Resources, Bugwood.org
Invasive Ludwigia peploides spreads by runners across the water's surface. Photo by Robert Vidéki, Doronicum Kft., Bugwood.org
The oblanceolate leaves of Ludwigia hexapetala, and invasive water-primrose. Photo by Kelli Gladding, FWC
Invasive water-primrose leaves are lanceolate (narrow ovals tapering to points) to oblanceolate (lanceolate with a more pointed base). Shown here are mature leaves of invasive Ludwigia grandifolia.


Reporting Invasive Species – FREE APP 
Midwest Invasive Species Information Network (MISIN)

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