Ask Mr. Smarty Plants

There seem to be two or three subspecies of this tree, Sideroxylon lanuginosum (gum bully), native to North America, but this one is the only one native to Texas, and is found in the Austin area. We looked and looked, trying to find propagation techniques and all sources agreed that it is propagated by seed.

If we correctly understand your question, you want to cut out a strip of root from which adventitious shoots or suckers have emerged and transplant to another part of your garden. Frankly, although we could not substantiate it one way or another, we don't think this would work. The root of the parent tree is also the root of those suckers. If you separate that root from the tree, the sprouts lose their source of nutrition and have no rootlets to acquire moisture from the soil. This tree has sharp thorns and not a great deal of landscape value, except as a barrier plant. If you do not keep the shoots trimmed down, the parent tree will form a thicket all by itself, but moving the thicket strikes us as pretty impractical. 

Since you have the raw material, there is no reason why you couldn't experiment, digging down to look for a rooted shoot and attempt to transplant it. We wouldn't recommend doing so right now, in our hottest and driest year in decades. Transplanting of woody plants by any means is best done in late Fall in our climate. Root suckers often don't have enough of a root system to support themselves. You can try to encourage development of an independent root system by cutting partway through the connection with the mother tree some weeks prior to transplanting.

Sideroxylon lanuginosum

Sideroxylon lanuginosum

Sideroxylon lanuginosum

Sideroxylon lanuginosum