Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants weeds going nuts....

Somehow, someway you got Eurasian Water Milfoil (EWM) in the pond. Raking it won't help - it spreads by seeds or by pieces of the plant breaking off and rooting. It's an invasive species. There are products on the market that kill it, but the best that I've found (although it isn't cheap) is Fluridone (Sonar AS). Navigate or Aquathol Super K also works, but you can use Fluridone and use a low enough dose so that only EWM is affected and not impact the other underwater plants in the pond. Treat early enough in the year so that it's killed before it sets seeds, or it'll show up again next year. By the amount that you have in the picture, it didn't just show up this year.

I would plan on treating it both this year and next year, as soon as the water started to warm up in the spring and it's actively growing. It's already set seeds this year, at least down here.