Ask Mr. Smarty Plants

Vitex or Chaste tree (Vitex agnus-castus) is a non-native species introduced to North America from China and India. Since our focus and expertise is in plants native to North America, it is really not in our purview. We can, however, point you to some general advice about transplanting trees. The USDA has a very good article about transplanting trees. Fall and spring are the best times for transplanting. The hole to put it in needs to be big enough—essentially, twice the width and slightly less than twice the depth of the root ball. Pruning the top growth by 1/3 and, if possible, root-pruning a few months ahead of time will improve your possibility of success. Also, root stimulator is sometimes useful.

You might also consider a native alternative to your vitex tree. There is always the possibility that non-native plants will escape from cultivation and become invasive. Texas A&M and the Texas Forest Service have an excellent online Texas Tree Planting Guide that gives you choice options for several criteria (e.g., your county, size of the tree, type of soil, etc.) for selecting a tree to plant.