I would hope that someone pointed out the the growers the conditions necessary for the Southern Blight fungus, Sclerotium rolfsii, to survive. That is damp, acidic soil at temperatures above 85°F. Not the ideal cultural conditions for growing Helleborus, which prefer a drier, but moist, alkaline soil. The fungus will not survive in alkaline soil. Can be eliminated by soil sterilization, so they probably aren't using a sterilized soil mix. Can also be spread by contaminated tools. When present, the fungal growth is exacerbated by the use of high Nitrogen fertilizer, which I'm sure the growers use to accelerate the growth of their plants.
I also would avoid purchasing from those growers and advise closely inspecting any plants purchased for a gray mold like substance around the stems at the soil level and soft tissue in the stems at the same level.
I have grown Helleborus for more than 20 years and presently have hundreds of them. Not once have I experienced a problem with Southern Blight and don't know of anyone else, including nearby growers, that have either.
Rb

Thanks, razorback, that's just what I hoped to hear!

On Tuesday, I took a sample of a hellebore into my extension office & just as I suspected, it was affected with Sclerotium Rolfsii. I do not know which hellebore it was... except that it is (was!) one of several huge specimens in that planting area. I'm hoping that the others do not develope symptoms.

I am sick & frustrated w/ fighting this disease in my gardens. For the past 3 years it has popped up in one bed or another. I am also a Master Gardener volunteer at the extension & our agent is a plant pathologist. We have pretty much decided that the fungus is getting spread around by all the squirrels & cats that visit my yard. I do my best w/ sanitation... but there is only so much you can do.

I am zone 7 am this disease loves our hot, humid climate.

I am a gardener in Maryland. I’ve lost a beautiful large leafed hosta and a nearby helllebore to what i suspect is southern blight. I‘m guessing that I did not properly clean up all the cicada “shells” and rotting dead cicadas that fell in my garden- too much dead debris around these 2 plants put in a woodland setting. Will be cleaning up! Just a guess on my part since I’ve never had this problem before with my hellebores or hostas.