duckweed in ponds
I am trying to find out about a product that will kill duckweed. We have a 1/2 acre pond with an inlet but no outlet. Duckweed is taking over. I heard about a product call Sonar A.S. It is safe for fish and swimming. We have large willow trees around our pond. Will it be safe for the trees. I need to get some kind of duckweek killer in the pond soon. The hot weather is making it grow very fast. Thank you for your help. Judy Willis
Union County Oregon pond and water gardens
Hello. There is a good summary of how to manage aquatic weed in the PNW Weed Handbook: http://pnwhandbooks.org/weed/other-areas/aquatic-weed-contol.
If you choose to use an herbicide it must be registered for aquatic use. Before using any chemical read the recommendations on the label. Towards the end of the article is a list of herbicides that can be used on floating weeds.