Ask Mr. Smarty Plants

Begin by reading our How-To Article on Container Gardening with Native Plants.

You can see from this USDA Plant Profile Map that Acacia farnesiana (Huisache) definitely grows in the Houston Area. You can follow the plant link to our webpage to learn more about its growing conditions, light requirements, etc. One comment on that page is that Acacia farnesiana can form dense thickets from suckers. This would probably be the first problem with growing it in a pot. The second problem is under Size Notes: Height 15-25 feet, Spread 15 to 25 feet. An ordinary root span is at least two times the height or crown size of the plant.

So, at the outset we would say the climate where you are would permit growing the plant, but we are not at all sure about the circumference of the roots going into a pot.  Since you mention espalier, which involves severe pruning of a plant, we see no harm in trying it. If at some point, the roots come out of the bottom or crack the pot completely, we would say it's time to take it out of the pot. Since you seem very adept at propagating the plant, you might consider them disposable; work on a few of them in large pots, or move them up in progressive sizes of pots, and enjoy them as a hobby until they break out of there. Or start them in pots, moving them up to larger pots as necessary and then plant them in the ground. But don't wait too long-the bigger they are, the harder they will be to transplant successfully.