Agapanthus is also known as Lily of the Nile or African Lily. The plant reaches 2 to 4 feet on average and spreads up to 2 feet. The plant's long center stalks rise in the summer to feature lavender/blue flower clusters atop. Hummingbirds are attracted to the flowers and the plant makes an attractive feature in flower gardens.
Agapanthus may be grown indoors. To enjoy their beauty, most people will have to grow them in this manner, as they do not tolerate many regions of the United States, growing outdoors only in the southernmost states--mainly California, Arizona, Texas, Louisiana and Florida (though they can be found in the southern tip of Nevada).
Crowding Is Key
Allow your Agapanthus to become a bit crowded or root bound to encourage it to bloom. If you notice a decline in flowers, it may be time to divide the plants. Crowding helps for a while, but then has a negative effect on bloom production.
Divide the plants (by axe) every 5 to 7 years and leave 18 to 24 inches between plants in the garden. Allow potted Agapanthus to dry out and they can be easily removed from pots for division. Increase pot size if needed, but leave only about an inch between the roots and pot sides. The plants may then require a year or two to recover and bloom again.
Be patient. A period of rest does follow flowering and some cultivars may tend to flower at certain times of year. Blue Danube, for example, flowers early. According to Michigan State University's Extension Service, Agapanthus does not depend on the length of the day to flower.
Disease can affect the plant more than pests, which are considered to be few and minor in effect. The Nassau County (Florida) Extension Service suggests that Botrytis can be problematic enough in the humid climates of the eastern states that only disease resistant varieties should be grown there.
Provide moist soil, with plenty of organic matter. The area should have good drainage and full sun; however, the plants can tolerate drought and partial shade. While Agapanthus enjoys the stress of being root bound, there is no evidence that other forms of neglect help force it to bloom.