Joe,
I've read that Hibiscus is nearly indestructible once established. Last fall I had some disease showing on mine and I trimmed off the sick parts. The sickness returned so I chopped 'em to the ground. This spring on a Friday in May, I saw a few sprouts peeking up. On Monday when I checked there were a dozen+ 18 inch tall stems showing. So, in my experience, It has been fine to chop down the sticks. I just did it again last week. Just leave a couple inches of stem above ground to prevent disease entering the cuts. I don't know exactly what kind of Hibiscus I have(it has dinner plate size flowers) but the info regarding the indestructibility of Hibiscus was gleaned from an article on Swamp Hibiscus.
Hope this helped.
Tyler

I've grown them for over 27 years (I have over 25 plants of different varieties) and always cut the stems back to where the plant still seems alive which is usually just above the ground. The most critical thing is to mulch them good to protect the roots and growing buds for next Spring.