Question
My mother, who lives in Ohio, called me this morning with a request that I do a web search fro her. She has several Hibiscus trees growing in her back yard. They grow to approximately 5-7 ft tall, and produce small light purple to light pink blooms in the Summer. She does not have a camera and I do not live in her city, so my apologies fro not being able to provide you with any photographs. She told me that there is a what appears to be some type of fungus growing on the branches of the trees. She said that it looks green and bubbly. I did some web research and was unable to find anything at all like she's described to me. Do you have any ideas on what may be going on with her plants?

Answer
I think I need to get a little more info before I can help you and your mother.

Can you ask her when the fungus first showed up?  I assume these trees are planted in the ground outside; Were the branches under snow this year?  Is it possible for her to remove the fungus by hand or spraying off with the hose?  Most fungi are not active at this time of the year, but if there was lots of snow and moisture, it might be some type of superficial mold/algae.

I look forward to hearing more information from you.