Ask Mr. Smarty Plants

According to Jill Nokes in How to Grow Native Plants of Texas and the Southwest:

"Most holly species are frequently and successfully transplanted from the wild or from field-grown nursery operations in the winter...."

Ilex vomitoria (yaupon), a member of the Family Aquifoliaceae (Holly Family), should readily transplant. The time to do this is now, mid-winter. It is very important, of course, to get as much of the root ball as possible when you dig up your trees. Here are some other tips in Transplanting Trees and Shrubs, from the Forestry Extension of the University of Iowa and How to Transplant a Young Tree from wikiHow.

It isn't very likely that this cultivar would be of any harm to your 'wild' yaupons even though there are, no doubt, genetic differences between the 'Pride of Houston' yaupon cultivar and your 'wild' yaupons. Genetic differences are the reason behind the improved cultivar's ability to produce more berries and have a different shape. Whether this cultivar was produced by selective breeding of trees that showed the desirable traits and/or propagated from cuttings of trees found with those traits, the forms of the genes responsible for the improved traits almost certainly are already present in some percentage of the wild population. Although there are transgenic crops being grown, producing them isn't a cheap or simple process; and, it isn't very likely that the beautiful, but humble, yaupon would have been given 'alien' genes to improve it.

Ilex vomitoria

Ilex vomitoria

Ilex vomitoria