I'm hoping my tropical pond house will be a close zone 9 this winter,those who water garden in zones 8 and higher.to you remove potted plants out of your pond over winter? Thinking that they may rot,as there are bulb plants.
Cannas and ear plants
I do take the pots out of my pond. There is only a Colocacsia Kona Coffee and a Crinum menehume this year, there have been others over the years. These plants are many years old and I routinely take the pots out and just leave them in the garden so the soil can dry out a bit. The water in my pond goes down to about 55 - 60 in late January/February, that would cause them to rot I think. If the winter is mild the foliage holds, if it gets colder than usual the foliage dies back and come up again in the spring. I like to divide and repot them with fresh soil in the spring before they go back in the water.
I'm in zone 9B and have never removed plants from pond during the winter. Of course some die on their own like water hyacinths. The umbrella and papyrus seem to winter well unless we have a real cold snap. In that case I take them out and keep them in the barn or some place out of the weather a little more. My water can go down as Ardesia's does but last year we had a very mild winter and plants just kept on blooming all over the garden and lived in the ponds.
Good luck with your plants. I would think they would be fine inside your pond house.
I'll keep a close eye on them,and wait to see how warm it stays on the inside,hoping the high humidity will keep the plants warm along as well the water in the pond.
I think the difference is bulbous plants vs. root plants. I never take plants like lilies, even tropicals, or other water plants out of my pond but find the bulbs on EE's do rot in the cold.
If I see the foliage dying back,I think then I will pull them out,but as long as they look good,they can stay in the pond.