I received a china doll plant in 2000,in the summer it is beautiful. It gets to be outside in the sun & warmth. In the winter when I bring it in the leaves start dieing off & it eventually looks like a stick in a pot. It has a few small buds on the "stick" but it basically looks just like a stick. What is the trick to keeping them growing & pretty in the winter time?? Please help me. Its a special plant as I received it when my grandfather passed away.