Any sudden temperature drops could cause both reactions

Hi
Temp drop in s. florida in sept.?? ,don't think so lol
In the past even into the 30's they merely went dormant.
These have been rotting at the roots .
Does look like 3 are going to recover though the dormant season has begun. Always something new in pond keeping lol gary

Hey Gary. I thought you were going to talk about how gorgeous your Water Hyacinth was this year.

The rotting roots are totally descriptive of the problem. It is called Root Rot. It is a fungal disease and there really isn't a lot you can do except get rid of the plants and not put any more in for a while. Too little oxygen is cited as a cause(???). However that doesn't necessarily address the presence of the fungus in the first place. Is it possible that some of the storms passing through your area picked it up from elsewhere and dropped it om your pond? That happened to my pond and lots of crops here a few years ago. For a while we had plant diseases that were simply not normally found here.

As a more remote possibility there is a disease called Rot. That one usually hits bulb plants though. It strikes plants that have a calcium deficiency. The entire plant, starting at the roots quickly turns into a sticky liquid goop. Any plant that has the disease must be trashed.(not in the compost) It spreads really really fast.(hours not days) The planting medium must be treated and rested for a long period or totally removed and replaced before replanting.

If it rained a couple of days before your Hyacinth began to rot, the first one is where my money goes. Sorry the news doesn't have a good side. The hibiscus could have gotten something else at the same time.

I did read a speculation from Florida that talked about controlling Hyacinth in waterways with plant diseases but I think you would have heard about that if someone actually tried it.

Here is a link that might be useful: Water Hyacinth Root Rot.

Hi
That must be it !!lol A new one for me Have never had a problem with WH as long as it had water . I usually remove at least a bushel a week during summer . Rains aklmost everyday during summer even more so this year 3 of the remaining plants seem to be recovering at least there is new growth. Was going to try some other kinds but WH is runaway the best water conditioner except when it rots lol Water lilies amazon swords and cryptocorynes have not been affected. Thanks for ythe info !!! gary