"Tom L. La Bron" wrote in message
...
Bill,

Water Hyacinths will be OK outside if the water temperature in the pond is
constantly over 70 degrees F. Any cooler and they will drop leaves, etc.
until the temperature rise into the 70's, which is my experience.

I won't be looking for water hycinths until late April or early May. I am
in Zone 7a.

Tom L.L.

Thanks, Tom/Hal.

The 70°F number makes sense. I know they were not doing that well when I
brought them inside, so I bumped up the temp to 77°F and added more
Potassium. They are doing quite well now, but I was never sure what cured
them.

I won't be seeing 70°F in the pond (Zone 5A) for quite some time. We had a
cool summer here last year and the WH did not thrive.