How to get Thalia Dealbata through winter?

About 3 years ago I planted a Thalia Dealbata in the small lake that is bordering the back of my garden in the Netherlands. As I suspected it not to be hardy, I took it inside during winter of the first year, where it barely survived. After this forum adviced me that the plant is reasoble hardy, I left it outside in the water next year and it survived perfectly. It now is a splendid large plant with nice purple ears, far too large to get inside again. As I understood the plant will survive as long as the roots which are about 30 cm below water level, will not freeze. Our Dutch winters are very mild the last few years, but a cold winter could come again. I would really regret to loose this plant, so I would like to know what to do if a winter with severe frost would come again. Does anyone has experience in protecting the roots of Thaia Dealbata (or other waterplants) from freezing?

Louis Harmsen

I live in north Florida, so our winters are not bad. It does occasionally freeze though. My thalia goes to the bottom of the middle of my pond.

I grow mine in a small tub that i heat in the winter. why not devide the plant ? keep a small part in your house for the winter . Regards Paul

Ik kweek mijn in een kleine ton die ik in de winter verwarm. waarom
niet devide de installatie? houd een klein deel in uw huis voor de
winter. Achting Paul PS my dutch is bad LOL

I live right outside of Baton Rouge, La. and mine winter over fine on the edge of my pond. It dies back but as soon as the weather warms up it is back up. In fact it re-seeds easily and you may find it a bit of pest popping up where it is not suppose to. They pull up easy though.

Jeri

Thanks Jerri, this helps me a lot because Zone 8b is quite similar to the Dutch coastal area where I live. Sometimes we may have temperatures below - 9"C, but that is very exceptional nowadays (climate change ?). So in I just will leave my Thalia Dealbata outside, like last winter. To be safe I will cut a piece of the root en keep it indoors like Phicks suggest. By the way, you are right that it tends to expand its territory quite quickly, ut until now I love that.

PS
I know that one has to be cautious with the interpretation of temperature zones, cause duration of cold and moisture also matter quite a lot, but being under water it seems to me that it mainly is the minimum temperature that counts.