Ask Mr. Smarty Plants

Our research didn't turn up a single mention of adventitious sprouts on Tecoma stans (Yellow bells). In fact, it is frequently used as a container plant, which indicates to us there is not a root problem. You obviously know about sprouts on other plants, many kinds of trees, including oaks, which can be unsightly and even cause invasiveness. In this case, you said you dug out the roots, so we think the roots are gone.

As to your question on whether a hibiscus would do as well in the same spot. We have a question for you. Why did you take out an obviously climate friendly native plant that is showy and low water use, to replace it with an hibiscus?

There are 9 species of the family Malvavaceae (mallow), genus Hibiscus, with the word "hibiscus" in their common names that are native to Texas. Most of these natives did indicate they would survive in the same conditions as the yellow bells, but several indicated a need for acidic soils (in Central Texas, most soils are alkaline) and high water use. However, we are betting you purchased a (probably) non-native tropical hibiscus, for their showy flowers. Here is an article from Clemson Coopertive Extension on Hibiscus.

 Bottom line: We don't really have a definitive answer to your question about sprouts, and we think your hibiscus will probably do all right, particularly if you prepared the hole properly and keep it well watered. It would not be our personal choice, as the Lady Bird Johnson Wildflower Center is dedicated to the growth, propagation and protection of plants native not only to North America but to the area in which they grow naturally. The reason for this is conservation of resources, including purchase price, water and labor.