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Water-primrose - Invasive Species Information

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What Is Water-primrose - (Ludwigia)?

Habitat: Aquatic. requires wet areas.
Distribution in Ireland: Sparse distribution.

Status: Established
Family name: Onagraceae

Common name/s: California water primrose; creeping water primrose; floating primrose; floating primrose willow; floating water primrose; marsh purslane

ReproductionWater primrose can be generated during all seasons from small fragments of stems or rhizomes. They can be broken easily by wind, water flow or animals. The plant can also reproduce by seed.

Water-primrose Flower

Water-primrose flower

Water-primrose have the ability to double their biomass from their broken particles between 15 and 90 days. This also allows this species to continue to thrive in habitat and regions where sexual reproduction cannot occur.

Water primrose is a species of flowering plant in the evening primrose family known by the common names floating primrose-willow and creeping water primrose. It is native to many parts of the Americas, but it can be found on many continents and spreads easily to become naturalized.


This species is well known as a troublesome aquatic noxious weed that invades water ecosystems and can clog waterways. This is perennial herb which grows in moist to wet to flooded areas.

How To Identify Water-primrose?

Leaf: Green egg shaped or slender leaf up-to 10cm long. Arranged alternately along stems.

Flower: Five yellow petals 1 to 1.5 cm in length. Each occur on long stalks that on each leaf axils. Flowers start from the stems which are floating or lying on the ground.

Stems: Green or relish brown, fleshy, smooth or with small hairs.

Water-primrose meadow

Water-primrose - Ludwigia peploides ID Guide

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Why Is Water-primrose A Problem?

Water primrose can form very dense (near impenetrable) mats in freshwater ecosystems. Large accumulations of this species can lead to a depletion of oxygen levels in the water while also competing with native species for space and resources.

Water-primrose Stand

The rapid and extensive development of plant populations can block waterways and thus disturb many human activities such as navigation, hunting, fishing, irrigation and drainage, reduce biodiversity and degrade water quality. have also been shown to have an alleopathic impact.

European Communities (Birds and Natural Habitats) Regulations 2011 non-native invasive plant species A-Z (Updated 2017)

There are currently 35 invasive plant species listed in the European Communities (Birds and Natural Habitats) Regulations (annex 2, Part 1)...


Click on a species from the following list to find out more regarding non-native species subject to restrictions under Regulations 49 and 50.

  1. American Skunk-CabbageLysichiton americanus

  2. Brazilian Giant-RhubarbGunnera manicata

  3. Broad-Leaved RushJuncus planifolius

  4. Cape PondweedAponogeton distachyos

  5. Cord-GrassesSpartina (all species and hybrids)

  6. Curly Waterweed - Lagarosiphon major

  7. Dwarf Eel-GrassZostera japonica

  8. FanwortCabomba caroliniana

  9. Floating PennywortHydrocotyle ranunculoides

  10. Fringed Water-LilyNymphoides peltata

  11. Giant HogweedHeracleum mantegazzianum

  12. Giant KnotweedFallopia sachalinensis

  13. Giant-RhubarbGunnera tinctoria

  14. Giant SalviniaSalvinia molesta

  15. Himalayan BalsamImpatiens glandulifera

  16. Himalayan KnotweedPersicaria wallichii

  17. Hottentot-FigCarpobrotus edulis

  18. Japanese KnotweedFallopia japonica

  19. Large-Flowered WaterweedEgeria densa

  20. Mile-a-Minute WeedPersicaria perfoliata

  21. New Zealand PigmyweedCrassula helmsii

  22. Parrots FeatherMyriophyllum aquaticum

  23. Red AlgaGrateloupia doryphora

  24. RhododendronRhododendron ponticum

  25. SalmonberryRubus spectabilis

  26. Sea-Buckthorn Hippophae rhamnoides

  27. Spanish Bluebell Hyacinthoides hispanica

  28. Three-Cornered LeekAllium triquetrum

  29. WakameUndaria pinnatifida

  30. Water ChestnutTrapa natans

  31. Water FernAzolla filiculoides

  32. Water LettucePistia stratiotes

  33. Water-PrimroseLudwigia (all species)

  34. WaterweedsElodea (all species)

  35. WireweedSargassum muticum

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