Ailing Hibiscus Tree

I have had a hibiscus Tree about one year. It started out okay though never had an abundance of blooms. I brought it inside for the winter and about the time to start taking it outside in the spring it suddenly dropped all the leaves that were left. No new growth has come on it. I started to throw it out thinking it was dead but noticed that the roots seem to be okay. Can anyone tell me what is happening?

 

try prunning it
not to much about 1/3, this might help it.
Al

 

Thanks, I hope this works.

 

The leaves may have suffered sunburn from the more intense light. Pruning seems a reasonable measure.