We have one of these too, and it's also about 18" tall. It's two years old and when we cut off a piece everyone was negative and said it would never live. Well it has.

I keep the extra limbs, that try to form, trimmed off so it will take on a tree like look. I have changed pots three times to keep it from becoming root bound and next spring it goes outside in the ground. This, plus trying not to overwater it, is all I have done, but then, I am not a gardner by any stretch of the imagination.

I grew them when I lived in OKC and one of my neighbors had some large bushes. They need some winter protection so I planted them up against a brick wall. They make a pretty bush but don't produce an abundance of fruit like they do out here on the east coast. But then again, there is a too-much-of-a-good-thing quality about figs sometimes. I would expect your trees to handle most winters fine but not forever. They are easy to start from cuttings so you should be able to keep some in a pot as backups.

Thank you for your help.
Ann