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Invasive Species: Water-primrose

The yellow, five-petaled flower of invasive Ludwigia grandifolia.

Invasive Species: Water-primrose

Watch list, detected in Michigan

This species is on the watch list and has been detected in Michigan.

What is water-primrose?

(Ludwigia grandifolia, Ludwigia peploides and Ludwigia hexapetala)

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

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. 


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.

Water-primrose photos

The following images can help identify water-primrose. Click on each photo for descriptions.


To report suspected water-primrose: 

Note the location of the suspected water-primrose and be sure to include at least one photo of the plant to help in verification. 

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.