Q.Hellebore Black Death
ALL of my hellebores (of which I have at least 20 throughout my garden) are infected thanks to a whitefly invasion that spread it everywhere. I’ve read a lot of articles that say to dig them out immediately and “destroy” them, but by what method exactly should I destroy them? I assume having the yard waste folks with the county take them for compost is a bad idea. Advice, please!

Certified GKH Gardening Expert
Burning will be the most common and effective way to deal with infected plant material, but depending on how proper one's composting technique is, it can be composted safely. If composting isn't done properly, it can spread the infection well beyond where it could have been stopped.
Bottom line- Burn it. Destroy it, completely. This is the only, real, way to be sure the infection is gone.