First record of Ludwigia grandiflora in Germany
Ludwigia grandiflora was first recorded in the wild in Germany in 2009 in North-Western Niedersachsen (Hussner, 2009). Dense growth of the species has been confirmed near Leer in Niedersachsen, in a former branch of the River Leda, a tributary of the River Ems. This stagnant stretch of water is 510 m long and on average 30 m wide with a maximum depth of 1 m. It is separated from the River Leda by an embankment. The population of L. grandiflora found was very dense, with several stands of different size. The old river branch has been used for fishing, and several fishermen commented that they had first observed the plant in 2004, but the pathway of introduction of the species remains unknown.
Considering the high invasive potential of this species and the fact that only one stand has been observed in Germany, eradication is strongly advocated.
Sources
Hussner A (2009) [Erstnachweis von Ludwigia grandiflora in Deutschland] (in German). http://www.aquatischeneophyten.de/
Nehring S, Kolthoff D (2011) The invasive water primrose Ludwigia grandiflora (Michaux) Greuter ; Burdet (Spermatophyta: Onagraceae) in Germany: first record and ecological risk assessment. Aquatic invasions 6, 83-89. http://www.aquaticinvasions.net/2011/AI_2011_6_1_Nehring_Kolthoff.pdf