Eichhornia crassipes (C.F.P. Mart.) Solms-Laub. (S-Am.) – A recent and very rare escape from cultivation (probably mostly a mere garden throw-out or relic of cultivation). It was probably first seen in 2001 in a ditch in the port of Antwerpen. In 2007 Eichhornia crassipes was also found in a pond in Poeke, near Aalter, and since then in several, more or less widely scattered localities (see here for an up-to-date overview of Belgian records: http://waarnemingen.be/soort/view/18820). It is probably often overlooked or merely neglected.
Eichhornia crassipes is very sensitive to frostbite and unlikely to become naturalized in the near future in Belgium. Single plants, however, may possibly survive mild winters in our climate (see also Wurzell 2000).
In the (sub-) tropics Eichhornia crassipes is one of the worst aquatic weed species, according to Gopal & Sharma (1981) even the most troublesome weed of the world. It is increasingly reported from southern Europe as well (see e.g. EPPO 2008).
Selected literature:
There is a vast literature on the invasive behavior, management and control of Eichhornia crassipes. Only a very small selection is displayed here.
Bruinsma J. (2000) Pistia stratiotes (Watersla) en Eichhornia crassipes (Waterhyacint). Gras is om in te liggen 71. [available online at: http://wimvdven.home.xs4all.nl/gras71.htm]
Carretero J.L. (1989) Eichornia crassipes en la comunidad Valenciana. An. Jard. Bot. Madrid 45(2): 568.
Coetzee J.A. & Hill M.P. (2008) Biological control of water hyacinth (Eichhornia crassipes) — the South African experience. EPPO Bulletin 38(3): 458-463.
Coetzee J.A., Hill M.P., Julien M.H., Center T.D. & Cordo H.A. (2009) 11. Eichhornia crassipes (Mart.) Solms–Laub. (Pontederiaceae). In: Muniappan, R., Reddy, G.V.P., Raman, A. & Gandhi, V.P. (Eds.), Biological Control of Tropical Weeds using Arthropods. 183-210. Cambridge University Press, Cambridge, U.K. [available online at: http://www.ars.usda.gov/SP2UserFiles/Place/66290000/TedCenterPublications/Center-OtherPublications/104.%20%20Coetzee%20et%20al%202009%20Eichhornia%20crassipes.pdf]
Coetzee J.A., Hill M.P., Ruiz-Téllez T., Starfinger U. & Brunel S. (2017) Monographs on invasive plants in Europe N° 2: Eichhornia crassipes (Mart.) Solms. Botany Letters 164(4): 303-326. [available online at: http://www.tandfonline.com/doi/full/10.1080/23818107.2017.1381041]
EPPO (2008) Eichhornia crassipes.EPPO Bulletin 38(3): 441-449.
Forno I.W. & Wright A.D. (1981) The biology of Australian weeds: 5. Eichhornia crassipes (Mart.) Solms. J. Austral. Inst. Agric. Sci. 47(1): 21-28.
Gopal B. (1987) Water hyacinth. ( (Aquatic plant studies, 1)). Amsterdam, etc.: Elsevier xii + 471 p.
Gopal B. & Sharma K.P. (1981) Water-hyacinth (Eichhornia crassipes) the most troublesome weed of the world. Delhi, Hindasia: viii + 128 p.
Hussner A. (2006) Die aquatischen Neophyten in Nordrhein-Westfalen. Decheniana 159: 39-50.
Maas H.E. (1992) Eine schone und gefurchtete Pflanze Eichhornia crassipes: Wasserhyazinthe. Palmengarten 56(2): 120-124.
Padgett D.J. (2001) Noteworthy collections and spread of exotic aquatics in Missouri. Castanea 66(3): 303-306. [available online at: http://webhost.bridgew.edu/dpadgett/Exotics%20in%20MO.pdf]
Piera J., Solanas J.L. & Crespo M.B. (1999) Mas datos sobre Eichhornia crassipes (C. Mart.) Solms (Pontederiaceae) en Alicante. Flora Montiberica 11: 12-14. [available online at: http://rua.ua.es/dspace/bitstream/10045/22326/1/Crespo_Flora_Montiberica_1999_11.pdf]
Rico E. (2001) Eichhornia crassipes (C. Mart.) Solms (Pontederiaceae), en Extremadura. An. Jard. Bot. Madrid 59(1): 160-161.
Simpson D. & Sanderson H. (2002) Plant portraits: 434. Eichhornia crassipes, Pontederiaceae. Curtis's Bot. Mag. 19(1): 28-34.
Téllez T.R., de Rodrigo López E.M., Lorenzo Granado G., Albano Pérez E., Morán López R. & Sánchez Guzmán J.M. (2008) The Water Hyacinth, Eichhornia crassipes: an invasive plant in the Guadiana River Basin (Spain). Aquatic Invasions 3(1): 42-53. [available online at: http://www.aquaticinvasions.net/2008/AI_2008_3_1_Tellez_etal.pdf]
Wurzell B. (2000) Water-hyacinth - twice. BSBI News 83: 42. [available online at: http://archive.bsbi.org.uk/BSBINews83.pdf]
Zamora C.V. & Chiamcharden U. (1980) Morpho-anatomical studies of Eichhornia crassipes (Mart.) Solms. Natural Appl. Sci. Bull. 32(1-4): 1-41.