| I think your columnea will do much better in a light soil. You can pot it and put it in a ziplock baggie out of direct sun. After it will start growing - keep taking tips off and sticking back in the same pot so you will develop a bushier plant. African Violets do root in water, but a lot of gesneriads will rot. Another easy to grow geseriad that some people call Goldfish - Nemathantus - is very happy to root in soil - but will refuse to do it in water. Offtopic:
Funny about these common names - - in Lowe's hardware I saw a nice annual looking plant with tubular orange flowers which was named Cornucopia and was refered as a hummigbird attraction. Why it was labeled Cornucopia - is beyond my understanding. I was able to track it by the hummingbird thing - and it is Cuphea ignea, or "cigar plant". Good luck with your columnea, they are lovely, keep it on the eastern or western window, they like to be on a cool side to bloom - and try more than one variety. Some are practically everblooming. Irina | 
