Where is it now? Inside or outside? It's 6 years old, so I'm going to guess it's a tropical? Dark shiny leaves? When you moved them back indoors, was it summer? How often do you water it? Have you repotted it? When? It may be pot bound, too big for the pot it is in, and when did you change the soil? Ever?

I have no idea where it is right now, but I'll take a shot in the dark and say if it's a tropical hibiscus, (shiny dark green leaves), and you haven't repotted it this year yet, get a bigger pot and new soil and repot the plant. If it is outside, water it regulary, when the top soil is dry, if the plant is inside, it needs a lot of sun, not as much water if you have air conditioning.

Good luck.