when to take cuttings of Tibouchina

My tibouchina in a pot  got tucked away behind other plants and has grown on unnoticed.  It now has long stems of old wood with equally long stems of new growth on their ends.  Clearly I have to do something.  Should I try cuttings incorporating a bit of old wood and trim them back, or try putting stems in a container of water to see if they will root?  Would they root as cuttings from this year's growth?  Should I grit my teeth and keep it going over the winter and take cuttings in the spring? HELP!