plumbago has brown stems, but still flowering
The brown stems seemed dry to me so I began more watering lately, but from what I am reading maybe the heavy rains we had earlier were the problem. Salvageable?
Oh yes, I also wanted to mention that if the plant has a lot of bare stems, you can prune them back. They do seem to flower pretty much all year, so I would wait till early spring, late Feb/early March, to prune back up to 1/3 the length of the branches.
Are brown stems the only problem? Do the leaves seem to be thinning, or are there spots or discolorations on them? And how long have you had this plant? Plumbago are very disease-resistant, but I have noticed that some of the newer cultivars are not as vigorous as the older ones. Also, it can take a few years for a plumbago to establish itself. I don't think that the heavy rains are a problem; I live in Florida too, and my plumbago really started to look nice after the rains started falling heavily this summer. This article does have some information you might find useful: https://www.gardeningknowhow.com/ornamental/shrubs/plumbago/growing-plumbago-plants.htm