Hibernacula is the botanical term for "winter buds"
Jimscott I think the plants would do well under those conditions. My suggestion is that if you get winter buds from any of your plants, you cull them and not pass them on as "Ivan's Paddle", and the same would be true for Ivan's D. rotundifolia "Evergrow" which is also going about, (which btw is not a registered cultivar name unless someone decides to publish it as should be done and Mr. Snider won't).
Hybrids often express qualities of both parents at times, and even if the plant is not a cultivar, it is treated as such by the community, so the standard form which commonly held as "a non-dormant form of D. anglica" should apply here as well and dormant buds would be out.
Peter, those are very beautifully grown examples of Ivan's Paddle!