Have never seen Lantana in tree form! Nice! To start a lantana tree, plant a small plant in spring, into a larger container. Begin shaping the tree as soon as new growth begins. Attach the stem (sometimes multiple stems) to a support like a bamboo stake, then begin trimming away any new side shoots.
Wish I would have know this trick over 4 years ago. It would have saved countless hours of taking sod out & would have produced healthy soil also! Put cardboard & compost over grass in fall & by spring... you have healthy beds to plant in!