Agapanthus makes a good ground cover and a lovely accent plant. Left alone, it will form a clump that can be easily unearthed and divided. Agapanthus may be deciduous or evergreen. Its display is quite similar to that of an allium or lily, but it stands alone in its own family. Agapanthus offers clusters of white, blue or purple flowers which look like miniature lilies. The plant is a good choice to add height to any arrangement or container garden. It also makes a striking stand-alone choice as a focal point indoors.
Propagate agapanthus by seed or by division (agapanthus has rhizome-like roots). When sectioned and replanted, the rhizome should produce true to the parent plant, with the same characteristics. Seed may not remain true or resemble the parent.
Divide outdoor plants in early spring, every five to seven years. Space the cut sections 8 to 24 inches apart. Partial shade should encourage showier blooms. The plant will adapt to full sun, but does not achieve the same level of performance.
Wait to divide agapanthus if you keep it as a houseplant. This plant prefers to be crowded and pot-bound to put on its most glorious display. It is sufficient to divide every four to five years. There is no specific time of year for dividing the (indoor) plant, but if you do so before it flowers, you may lose that year's round of blossoms.
Divide the plants by cutting apart the rhizome with a sharp knife, leaving roots on each individual section (according to the Wisconsin Horticulture Master Gardener Program). Use one plant per 12-inch pot. Plant the divided rhizome (whether indoors or out) slightly beneath the surface of the soil.
Sow agapanthus seed in early spring, but be patient--the seed can take up to four months to germinate and up to five years to flower. The seed may require warmer weather to begin to take off. The seed is not known to store well; choose fresh seed and plant it as soon as possible.
Use a soil with good drainage and moderate fertility. The plant will tolerate a number of soil types--and even drought conditions--once established. Use a light hand with fertilizer. Overfeeding can cause the plant to grow rangy and produce more foliage than flower. The University of Florida recommends disease-resistant varieties for humid climates, such as those found in the eastern United States.