This past weekend southeast Texas had two of the coldest nights we've had in three years. Lows in the teens and low 20's from Huntsville to the coast. In fact at one point Saturday morning, every reporting station in Texas had temps below freezing!
Temps like this will damage unprotected tropical plants. The plants in my yard look like mush and many are probably gonners.
However, all is not lost. Over the years I have found that my Hibiscus will often come back if I simply cut off all the branches down to the stump and leave it be until spring. It usually grows back even with heavy freeze damage.
My Lantana, same thing. Just cut it back down almost to ground level. It looks terrible, but Lantana is famous for coming back in full force once the weather warms back up.