Do you have a cold frame? A greenhouse is a brilliant asset but since not many of us can spare the space for one, a cold frame is a good winter protection for tender cuttings. Yep, the top growth may die back but it is the roots where the action is so as long as the pots do not freeze for weeks at a time, they should be OK. If your winters are too cold, then simply keep them in a dormant state in a garage or basement - they are not dead, just resting. I sow a lot of my seeds all year round and frequently have cuttings to overwinter from summer...and I just assume that the plants 'know' what they are doing, will go into dormancy and when the conditions are right, will start to grow top growth again the following spring. There are always losses, especially with tender pelargoniums, which are susceptible to over watering (I keep mine practically dessicated now) but if the cuttings have developed enough roots, they will be perfectly OK coming through the winter.

Lantana camara is invasive, but there are sterile cultivars. Lantana montevidensis was once touted for not producing viable seeds, but the invasive status for this plant has changed to invasive in some frost-free sections of states (Florida, Gulf states and California mainly). It is not as invasive as the species L. camara, however.

@floral_uk I probably did read the label when I bought the seeds. First time grow from seeds so did not really pay attention. Bought other seeds too, but they did not sprout. So thought this might be weeds. @wantonamara: wow, they indeed have those? I was half joking when I said tri.. quad... @windberry, thanks for the tips. That's what I will do. Wait for the flowers see if I like them and then let it reseeds. It is a long periods from seeds. Talking about instant gratification...:) thanks all!

If you keep up with it, it will be gone in a couple of years. You'll always miss a few bits of rhizomes, but you'll get them later when they sprout.