Agapanthus africanus is typically known as Lily of the Nile, although they are not true lilies (They are in the Amaryllis Family) and most are native to South Africa, from the Cape of Good Hope to the Limpopo River. They bide their time growing as strap-shaped leaves most of the year, but in the spring produce a most flamboyant display of blue flowers. Ours are in containers and ready to go for the coming Spring!
For container plants, plant the rhizome 1/2" below soil surface, keep soils consistently moist and provide moderate fertilization during the growing season (spring and summer). Plants bloom best when roots are pot-bound. Site containers in locations with afternoon shade. In fall prior to the first frost, remove containers to a bright, frost-free location for overwintering. Provide very limited water in winter (just enough to keep leaves from drying/wilting).
If you are adventurous, you can try growing them in the ground (with heavy mulch for winter protection), if you are colder than zone 8.