Just replant the tops of the rotala and they should bounce back. Usuay affter a trim i dose woth a little flourish comp after. If there's little to no algae in the tank, the rc's start chompin on the plants. When that happens I usually throw in a couple of algae wafers.
Btw where did you get your rcs from? I'm looking for a couple for my heard, I got keep the genetics different.