Do you have any information on what I believe is Black Death of Hellebores. My mature Hellebores are infested with what looks like tiny white aphids a...
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Hellebore Black Death #321137
Asked May 12, 2016, 4:39 PM EDT
Do you have any information on what I believe is Black Death of Hellebores. My mature Hellebores are infested with what looks like tiny white aphids and the inner leaves and stems are turning black. Help. I think this is viral which means remove and clean up. Any ideas and how do I keep it from spreading to my other hellebores?
Montgomery CountyMaryland
Expert Response
Hellebores get lots of diseases that cause the old leaves to turn black. Remove all affected foliage. The hellebores tend to recover nicely after the affected foliage is removed. There is a virus that is referred to as "black death". From your description, we cannot say whether you have the black death in which the plants should be removed immediately or if you have a more common leaf spot disease in which the affected leaves should be removed. Black death is seen primarily on new foliage and flowers of mature plants with blackening along the leaf veins, dark streaks or ring spots on petioles and bracts and stunted blackened new growth. We would suggest removal of plants with blackened new growth. There is no spray that would be of benefit. Sanitation is of fundamental importance. vw
Additional information:
the plants are really infested with aphids -tiny whitish but under
magnification are green. There is blackening of some of the bracts-photo;
black spots on the new growth but more noticeable on old growth with perhaps a
bit of distorted growth on the new foliage ((photo); I didn't see
blacking on leaf veins. I have a large number of hellebores in my garden
- in front yard and back. It looks as if nearly all have the aphids but
to a lesser degree in the back yard and not sure there is as much blackening.
Being in Bethesda, we have had rain, rain, and rain. I hope the
photos help. If there's a chance it's not Black Death, requiring removal
then what might it be and how do I deal with it? Many thanks.
Remove the blackened foliage. If the new growth develops blackening, remove the entire plant. If you do not like the aphids, squirt them off with a strong stream of water or soapy water. Again there are many diseases that cause black spots on hellebores and this is certainly a good year for fungi. These diseases other than black death are handled by simply removing affected foliage. vw
