I have a 5-year old elderberry bush that bloomed normally this spring. However, it then began shriveling up and dying branch by branch. I have cut off all the dead branches and have only two small ones left. What caused this to happen? What can I do to protect the small section that is still alive? Will the plant rebound next year, or should I plan to replace it?
This sounds and looks like Verticillium wilt, an often fatal fungal disease. Elderberry are among the group of plants that are susceptible. Unfortunately, this means you can not plant a susceptible species in that area. Here is more info including a list of most and least susceptible plants. http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/cankers/verticillium-wilt.aspx
Additional info: http://www.canr.msu.edu/ipm/uploads/files/woodylandscape_pdfs/verticilliumwilt.pdf