I only have information about the edible, non-ornamental kind of purslane, but I have been able to keep one plant alive in a container for over a year, in Phoenix's warm winters. December and January are very hard on them. They have to be brought inside at night and put under a grow light and kept warm, and then they need to be put outside in full sun during the day. They were able to survive this way for about a year and a half, but then the hard water deposits (salts) built up in my container, and they ended up dying out anyways. I think if I have used filtered water they might have survived even longer.
