Do you have a pic? A shrub can take a few years to establish. Sounds like you put them in last year? Morning light only is not enough for Lantana to be all it can be.

These below usually die to the ground in winter, get 6+ feet tall every year but the season is a little longer here. Not necessarily an attractively-formed plant unless manicured to be such. These haven't been touched for a couple years. I wouldn't put many, if any, in a front yard, for aesthetic reasons, and because the city sprays for mosquitoes. Since they are constantly covered with butterflies and humming birds, that would not be good. Hopefully the spray doesn't get back to where these shrubs are much, if at all. Sure doesn't kill the mosquitoes either.