Diseased Hellebore

Asked September 11, 2020, 3:03 PM EDT

My Hellebores have a disease that starts at the tips of the leave and moves to involve the entire leaf. Most online articles about fungus on Hellebores do not describe this pattern of advancement along the leaf. The leaf stem is also attacked.

Genesee County Michigan

5 Responses

More information about the growing conditions of these plants would be helpful. I'd like to know the amount of light they receive and if there have been any recent changes to that. Is this area irrigated? Also, it would be helpful to know more about the population of hellebores you have. Do you have more than one type and do you see these symptoms in all of them?

I have only two hellebore plants. Both have these symptoms. They are nursey stock and were planted about 8 weeks ago. They are in a bed under a weeping willow tree and are mostly shaded but get about 4 hours of late afternoon sun per day. The area is irrigated with a weeping hose, covered by mulch.
Thank you for your help!

Newly planted plants are more sensitive to heat and drought stress. It sounds like these were planted during the hottest part of this summer and preventing drought and heat stress at that time would be very challenging. Afternoon sun is also quite intense and can lead to leaf scorch. I will consult a colleague on potential disease but this has more indicators of environmental stress.

Thank you for your reply.

I followed up with a colleague who concurs that this type of die-back symptoms can be from heat/drought stress but that hellebores are also susceptible to a type of botrytis root rot with die-back symptoms due to loss of root tissue. We would not be able to differentiate those by photo alone. If you are interested in investigating potential root rot, you would need to submit a sample to the diagnostic lab. Their website has good advice on collecting the appropriate type of sample if you choose to pursue that avenue as well as sample submission instructions. https://www.canr.msu.edu/pestid/submit-samples/

It would be good to directly check the moisture level of the soil under the mulch by digging under the mulch and touching the soil. You are supplying water but plants under a tree are competing with tree roots for water. Depending on the amount of water you are supplying and your soil type, you could have very wet or very dry conditions.