I grow mini-Agapanthus in containers. So far I have observed that they need at least 6 to 8 hours of sunlight, so you can get many bloomstalks. In my garden it only gets 4 to 6 hours but still manages it, I just put it in the sunniest area of my garden. Over here where we are almost always dry, it surely likes being watered. But once it is well established it is drought tolerant. That's why I like it too for its drought tolerant attribute.
I see a lot of the regular Agapanthus in parking lot islands here and in front yards, and they do bask in full sun..so maybe position your plant in a sunnier side to get some blooms out. I get my blooms in June, so that is really hot weather days here where we get triple digit heat and lots of sun too.
