I have been growing Agapanthus in the Charlotte area for the past 10 plus years. While I have experienced the same thing you have with plants just withering away, others have done well for years. One thing I have observed is that some seem to be cyclical in their blooming with a stellar bloom display one year followed by a year of rest with few to no blooms.

What selections have worked for you Palm Nut?

Unfortunately, I have the same story as you, chezron. I planted three agapanthus last year that were in full bloom. Many seed heads produced as well that I didn't bother to retrieve. New growth came up this season, but no blooms yet. I just moved them this past weekend about a foot closer to the foot path, as I thought maybe the large azaleas behind them were shading them too much, so they'll receive more direct sun. They had healthy roots at least! We'll see if they bloom. Of course, earlier in the spring I also bought and planted three Queen Mum Agapanthus, which were not in bloom, to plant on the opposite side (which does get more sun). They bloomed nicely about a month ago, and lasted for about three weeks, which was a little disappointing (thought they would bloom much longer).

Chezron, about the only ones that have been duds have been the variegated varieties, any of the black stemmed ones, and anything from Plant Delights.