Hi neighbor - I too , am in Texas.
I have one that was given with no i.d.
It was a 12 inch piece. I waited for roots to come out then planted according to the pitaya website instructions.
It grew by leaps and bounds, got to 3 ft. tall- no flower or fruit. But, I am sure this year it should flower and fruit.
Please, check back with me in the season and I will post an update. Good luck, Mistee

I just attended a seminar and the presenter said in their native habitat, the dragon-fruit is pollinated by a particular species of bat and moth. In other words, the flowers should be pollinated at night, so get out your flashlight and little paint brush :-)

mine produced huge flowers last year but no fruit. This year I hope it recovers from the dang winter! They won`t produce fruit until the plant weighs about 10 pounds, but will produce flowers a season or two before producing fruit.
I know several people who get fruit from theirs, hoping to get some this year and putting in 2 more types.
Good luck!
Try the Texas rare fruit growers, I think they had a website and some of them post in the tropical fruit forum.
Tally Ho!