I put my plant in the ground a couple of years ago because it tended to get gigantic in pots. I was constantly rooting cuttings to start new plants which could replace the mother and take up less space. Once it was in the ground it slowed down greatly, probably because it was getting water half as often and never getting nutrients. Still flowers, though.
It is much more active in summer and early fall, which is when it did most of its growing when I had it in pots. My in-ground plant seems to suffer a bit from our total lack of rainfall during its active period.
The plant in the picture needs more light and will tip over out of the pot, at the rate it's going. Like Stush pointed out, a sideways and downward growth pattern is totally normal. For a while I was growing mine in a big pot on top of a clay chimney and it filled in nicely below, to the point where most of the plant was below the level of the soil. In order to keep your plant as compact as possible, given this behavior, very strong light makes a difference. My plants were always in full sun. Indoors try to provide hours of daily sun. The plant will fill whatever size pot you give it but I would think a container with about 4 times the volume of the current one would be about right in the near future.
