[Subtletanks91]

I found these looking for invasive, illegal, and other wise anticipated invasive species of California to learn a bit more. I'm surprised to find out frogbit. Elodea. Water hyacinth. Giant salvinia among other are on this list.

http://www.sfei.org/nis/NISguidebooklowres.pdf

http://plants.usda.gov/java/noxious?rptType=State&statefips=06

 

[Diana]

Though not on the list, the other Salvinias are suspect because they cannot be told from the Giant Salvinia when they are young.

I have not been able to get certain plants at my favorite pond supply store for several years.
Water Lettuce is one. They do not sell any Salvinias.
I know that the Water Primrose is also considered an invasive weed.