Which floating oxygenator type plants live in 50 degree water temps to help reduce green water?

We're in western WA and the pond is in part shade with 3 goldfish plus perennial pond plants.

I already know that water lettuce & water hyacinth are for warmer weather, so will wait to purchase. When I look up Azolla, anacharis, dwarf sagittaria the info states 72-82 degrees.

Do we just need to wait for the perennials to wake up a bit more?