Q.Problem with Hellebore
I seem to have a continuing problem with my Hellebores. They will do fine for a few months, bloom in early winter and then they start to wilt and then start rotting near their roots. They are planted in pots in a shady area with good drainage. I do not water much at all. I have replaced them many times because I love the bloom (Christmas Rose). I’m to the point of not replacing any more.
Certified GKH Gardening Expert
Growing in a container requires some extra attention, such as more water in the summer. (All container plants in summer need more water than in-ground plants.) Hellebores need a rich soil, so if you use plain potting soil, add some compost to enrich the potting soil. It doesn't sound like a disease since you don't mention spots or other fungal symptoms. So, I would focus on the cultural requirements of hellebores.
Here are more tips: