Oops ! My plumbago dies! I failed to add that to my previous post. It never lives through the winter but no one else seems to have that problem.

the light blue Cape Plumbago that shows up in nurseries in late spring is a tropical plant from South Africa and won't survive temperatures below 30 degrees. I used to bury the pots in my front border and then remove them to a corner of the garage where they would not freeze. I've been able to keep them for a couple years this way here in coastal SE Virginia 8A.

There are other shrubby plumbagos that are winter-hardy but they die back each year. Look at plumbago ceratostigma; beautiful blue flowers contrast with foliage that has touches of red. The common name for this one is leadwort; not as showy as lobelia but much of the same charm for edging.