Water-primrose (Ludwigia spp.)

Synonyms: Ludwigia peploides, Ludwigia grandiflora, and Ludwigia hexapetala

Common Names: Creeping water-primrose, large-flower primrose-willow, Uruguay water-primrose

Description: Non-native Ludwigia (L. peploides, L. grandiflora, and L. hexapetala) are very difficult to tell apart.

Habit: Large, mat-forming, emergent and floating herbaceous perennial.

Leaves: Alternate on stem, variable in size and shape, lance to egg-shaped, growing up to 3.5 in. long, smooth margins and either hairless or with long, soft hairs.

Stems: Glabrous or pubescent, fleshy, reddish in color 8in. - 2 ft. long that creep horizontally as well as grow vertically.

Flowers: 5 petals growing from leaf axils, bright yellow in color, 7-24 mm long and bloom in late July to August.

Fruit and seeds: 5 angled capsule, 3 cm long containing 40-50 seeds. Seeds are 1 - 1.5 mm long and embedded in the inner fruit wall.

Habitat: L. peploides is native to Australia, New Zealand, North and South America. While L. hexapetala and L. grandiflora are native to Central and South America.

Reproduction:

Monitoring and rapid response: Small patches can be hand-pulled, be sure to remove all stem and root fragments. Large infestations can be controlled using herbicides registered for aquatic applications.

Credits: The information provided in this factsheet was gathered from CABI: Invasive Species Compendium and the King County Noxious Weed Control Program.

Individual species images that appear with a number in a black box are courtesy of the Bugwood.org network (http://www.invasive.org). Individual photo author credits may not be included due to the small display size of the images and subsequent difficulty of reading the provided text. All other images appear courtesy of Google (http://images.google.com).

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