Hibiscus help, please

Unbeknownst to me, someone dropped off a 5 foot hibiscus at my house yesterday. No dirt, no water, just set it on the asphalt outside the garage. As soon as I discovered it, I put it in a tub of water and let is set about 4 hours, but it was already wilted. I planted it and mixed in some well composted horse manure and watered it well. Now, it looks even worse. There was quite a bit of root damage. I am wondering, should I cut it back, now. In the past, I've always waited for them to die back, then I cut in late fall, but I don't want this plant to be any more stressed than it already is.
Comments? Suggestions?
blpender

Just let it be - it will be ok.

BL - how's the plant doing?

Thanks for asking. The leaves are all crispy, and the top part of the branches are withered, but I would expect that at this time of year anyway. I will be cutting the others down in a week or so, and may do this one as well.