Question: For 20 years I have had a clump of monkshood that comes up vigorously every spring. About June the bottom leaves blacken and drop. It manages to put out a flower or two, but it is getting worse each year. I gave a part of this plant to a niece, and she won a prize with it! I’ve moved mine three times with no success. So I must be doing something wrong.
Answer: At first I thought the monkshood (Aconitum spp.) must be diseased, but if a division of it won a prize, you’re right: something is wrong with its culture.
Monkshood requires a rich but light and friable soil that drains well. It thrives in either shade or sun, but if in full sun it must be well watered by deep, slow soaking. Spring feeding with a granular 5-10-10 usually is sufficient, but if the plant looks a little weak by July lightly side-dress again. Once established, the monkshood does not like to be moved. Never transplant if it is not necessary.