What is going on with my hellebore? Part of the stalks became yellow black and weak. Was able to pull out a steak easily.
Bought the plant 1 year ago. Did well up until a few weeks ago. It’s been hot and humid where I am.
This looks like Hellebore leaf spot disease.
Hellebore leaf spot is caused by the fungus Microsphaeropsis hellebori and is a common disease on many hellebore species. You are most likely to see infections when new plant growth is occurring from late winter until summer.
Remove all affected leaves promptly and destroy
Do not allow dead, infected material to remain around the plants, since this will be a source of infection in the following season
The spores are spread in water and wind-blown rain and thus wet conditions are required to initiate disease. The fungus perpetuates on the plant over the summer and autumn and a new round of infections is intiated at times when new plant growth is occurring.
There are no fungicides with specific recommendations for the control of hellebore leaf spot. However, the fungicides tebuconazole , tebuconazole with trifloxystrobin , and triticonazole are labelled for the control of a number of other diseases on ornamental plants, and may give some control of hellebore leaf spot .
Hellebores are generally quite expensive so I understand the concern. You mention the plant is new, so perhaps the seller will guarantee the plant.
Helleborus argutifolius or holly-leaved hellebore can be more resistant to this disease.