Your lantana might not even be hardy in your location. It's not in my zone 7. Anyway, even if it IS root hardy, the top will die back completely after the first hard frost. It will need to grow back from the roots.

Lantana 'Miss Huff' and other Lantana cultivars are root hardy for me and many of my neighbors, Freezing temperatures will kill all or most of the above ground stems, but they generate new growth rapidly in the spring.
I don't remove the bare stems until new growth appears in the spring. They can be an eyesore during the winter, but cutting the hollow stems can allow water to enter, then freeze and kill the crown & roots. If you must remove the bare stems for appearance purposes, it would be advisable to cover the plant with a waterproof material and then a mulch.
I would wait until spring to purchase one. It will then have an entire growing season to become established and then harden off for the upcoming winter.
Lantana's are available in many sizes at nurseries in my area, from 4" pots, up to 3-5 gallon sizes, at nurseries catering to the landscape trade.
A one gallon size should reach mature size by it's second or third year and then began to spread laterally, which, if unchecked, will form a HUGE plant. They require lots of direct sunlight to grow and bloom well and once established, are extremely drought tolerant. I didn't water mine during two consecutive years of severe and exceptional drought and they didn't appear to notice.
Some other attractive cultivars that are readily available, are: 'Dallas Red', 'New Gold' & 'Pink Caprice', plus others, depending upon locale.

Yeah, 'Miss Huff' is NOT a good cultivar if you want a plant that stays under 3', even when it is killed back to bare lower stems in winter.

Does it have to be a lantana you plant? Dang, those nasty things are all over the South.

ha ha...well I actually love them. Of course I don't HAVE to plant the lantana, only because I like it. And the 3' bush was a minimum height, not maximum. the current bush is 6 feet tall and 4 feet wide! So based on what everyone has said, I think I would like to plant it in the spring. My only concern is for children trying to eat the berries...since they are poisonous. that is the reason I decided them in containers this year.