Should I prune my lantana each year

I do, each spring. I cut-out any dead-wood back to living, all thin shoots and trim the rest to the shape I want - bush or standard . They are very vigorous growers in summer if watered well, easily putting on 10" - 20" of growth , and becoming straggly - so they may need space. They grow well from seed set about now, with luck flowering in the first year.