Left outside all winter the stems began to rot and disease spread down the stems until it reached the leaf rosettes. At this point I began to cut off the best of the rosettes and, after a day of drying, set them in a bed of pumice. As rot continued to spread down the remaining stems I realized that more drastic measures needed to be taken.
Yesterday I made the decision to pull everything out and redo the whole basket. The remaining rosettes were hung out to dry in the mesh potting shed bench.
The rosettes planted in the pumice have all rooted. Pumice is the most incredible medium for rooting.