Question
Hi I live in Southern California and the temperatures have been in the mid-20's at night.  I have three gorgeous Hibiscus tree/shrubs in my front yard.  They are over 6 ft tall.  After last nights freeze the leaves all turned brown and died. Do you think the plants themselves survived and will "come back" in the spring?  I was not able to cover them.  Thanks for your time.  

Answer
Jen, If the ground froze your Hibiscus is probably going to die; if the ground didnt freeze, it may have just stressed from the cold; this is a normal reaction, and the plant should regenerate; check the trunk by scratching a small (half inch) area of the bark, if the phloem layer (inside the bark) is still green then it should be ok. you will know within a couple of weeks; if the phloem starts turning brown then the tree is indeed failing...good luck Nick.