I have some growing that I started from seed harvested from one of my 30 year old agapanthus that bloomed last summer. This is the tender variety. Yes - I hate lugging them in and out.
I did nothing real special. Started them in regular seed starting media that I watered with Hydrogen peroxide solution which I use for all my seeds and seedlings.
I secured some hardy Agapanthus and planted the bulbs last fall. They were small, but they did bloom and are now going to seed. I will be trying some of them as well.