Maybe it would help if you could tell us what kind of symptoms of stress or decline you were seeing before/as you were losing the plant.

I'm not growing it but I'm seeing it more frequently in nurseries. There doesn't seem to be anything out of the normal growing conditions for rhododendron in caring for it, other than suggestions that it may be more sensitive to wind. Also hardy to approx 5-15F, you may have come close to the 15F last December - did you lose the parent plant over winter or find it failing during the growing season?

The plant was dying back, branch by branch, in late fall. That's when I tool off three little cuttings and potted them up in the greenhouse. One took. The mother plant was located in a very sheltered area. There's no wind, and we certainly didn't get below about -10 C. (I think that's about +8 F) in the coldest part of the property. With the forest as a backdrop, there's a lot of biomass warming that area. Since all the other rhodos and azaleas in area survived unscathed, I'm just wondering if this specie is much harder to grow?