I have about three acres of a backwater area that has water lilly covering the surface. I am not sure which species it is, and whether it is helpful or not. The leaves are very large, up to 10 inches and slightly oblong. There are yellow flower buds right now. The buds are about an inch in diameter. I want to use this area for waterfowl. The plants seem to be very prolific and are spreading out over the entire surface area. What can I do to control them?

Tricky, when you have a large number of healthy plants clogging a large pond, if you try to treat the whole lot with chemicals you end up with one very polluted pond full of decomposing plants. Perhaps there is a technique for chemically treating a small area at a time, so in steps you dont have too much dying at a time.

the water lily sounds like the native nuphar, for what its worth, they could be yanked out fairly easy manually with a simple hook on a pool, once you got the knack of it you could clear maybe 50x50 sq ft at a time, not such an unpleasant chore splashing about on a warm sunny day...

Regards, Andy

Disclaimer... I have NO affliation with the companies named below.

Dow Chemical makes a product called Rodeo that will kill water lillies w/o harming the fish. The price is $250.00 for 2½ gal.

SePro makes the SAME product called AquaPro. It's $52.00 a quart delivered. You may call SePro at 800 419 7779

Good Luck.....

Monsanto, after selling the brand-name RODEO to Dow Agrosciences 2 yrs ago, introduced AQUAMASTER - a 53.8% glyphosate formulation - which costs approx $180 per 2.5 gal.
Cerexagri has also been marketing AQUANEAT, another 53.8% glyphosate product, in 1-gal jugs. Cost runs about $75/gal.
With all previously mentioned products, it is imperative that a surfactant (wetting agent) be tank-mixed with the herbicide for maximum plant activity.