Our climate is perfect for growing agapanthus (Agapanthus africanus), also known as Lily of the Nile or African lily, even though they are not in the lily family. With large masses of blue, purple or white flowers borne on long slender stems, the hearty agapanthus makes quite an impression in the gardenscape with very little care. Native to regions of that share our same temperate climate, these virtually cast iron plants flourish here. In colder frosty climates they are kept as prized greenhouse plants, which seems funny since they literally grow like weeds in most of.
The agapanthus grows from an underground rhizome, which is a horizontal underground plant “stem” that produces roots and holds onto nutrients and water for the plant. The agapanthus rhizome produces thick white fleshly roots and sends up shoots above the ground that turn into lush evergreen leaves.  
Around June, long stems shoot up from the plant, which can range from 2 to 4 feet in height, depending on the variety. The stalks are topped off with a large bud that eventually opens into a burst of star-shaped flowers that resemble a dazzling fireworks display exploding against the sky. Use them as cut-flowers in a 4th of July flower arrangement using, blue and white agapanthus, red Gerbera daisies and white hydrangeas.
You can grow agapanthus in both the garden and in containers and they prefer fertile, well-drained soil, as well as a sunny location. In hotter areas, you can plant them in partial shade, but along the cooler coastline, they need the sun to produce an abundance of flowers. Considered to be a drought-tolerant plant once established, they also do not require a lot of water or fertilizer to thrive. After the flowers fade, cut back the flower stalks.
About every four to five years in the fall after the hot weather has passed, you can divide your plants and replant them in other areas of your garden or share them with friends. Cut back all the leaves and dig up the rhizomes, being as careful as possible not to damage the plants root structure. Divide the rhizomes using a sharp knife and replant the rhizomes, root side down and giving them about 2 feet apart from each other. You can also feed them a little Super Thrive to keep them from going into shock after they are replanted. Cool fall months are the best time to divide your plants or add new ones to your garden.
If you grow agapanthus in containers, they prefer to be somewhat root bound in their pots and they should be fed in early spring with a diluted organic fertilizer, since nutrients diminish faster in container soil than in the garden. If the pot they are planted in made from a medium, such as clay they will need more water because the clay will dry out the soil quite fast.
When handling these plants wear gloves, since they are considered to be poisonous and their sap can irritate the skin. If you have dogs or cats that chew plants, even though they are considered minimally toxic, you many want to keep them in an area away from your pets, especially after cutting or digging them up.