Experts and BHG readers answer.
buds on hibiscus bush
Thanks for writing. I'm sorry, but I'm not sure what the problem is. I've been doing some research and I haven't come across anything that just affects the buds and makes them turn black.
Your best bet is to consult the folks at your county cooperative extension service at http://web.extension.uiuc.edu/ajmpu/ --- they should be able to help more, especially if can bring them a sample of the affected buds to examine in person.
---Justin, Senior Garden Editor, BHG.com "