Remove the plant from the pot and cut away discolored or mushy roots. Then repot into fresh, dampened potting mix. Make sure drainage is good. Pots should have adequate drainage holes in the bottom, ...
The last week of December is time to check your overwintering plants to see if they need just a bit of water, those geraniums stored in the garage, the dahlia tubers tucked away and abutilon shoved ...