Agapanthus, or African lily, propagates well by division. Gardeners may also collect and sow seeds from their plants, but plants grown from seed may not be exact copies of the parent and may have different colour blossoms, according to the Royal Horticultural Society. The best time to divide agapanthus is between spring and early summer, or in early autumn when the plant is done flowering.
Insert a garden fork beneath the roots and lever the plant up out of the ground firmly but gently, starting at the centre and working out.
Shake off excess soil.
Use an axe, sharp knife or saw to roughly cut the root clump from top to bottom, splitting the parent root clump into the desired number of new plants clumps. Each new clump should have three to five healthy shoots. Leave as much of the parent plant intact as possible and replant it in its former location, filling in around the roots with extra soil.
Plant new clumps as soon as possible and water them thoroughly.
Agapanthus may be planted individually in pots 8-9 inches in diameter filled with potting compost.
Move pots to a dry, frost-free place in late autumn.
Collect agapanthus seedpods in the fall.
Allow pods to dry indoors until they split apart; the amount of time needed will vary. Store seeds in a cool, dry place over the winter.
In the spring, sow seeds indoors in shallow seed trays using seed compost. Cover completely with a thin layer of soil. The seeds with germinate in 70- to 80-degree Fahrenheit temperatures. Germination takes 3-4 weeks, or occasionally 2-3 months.
Individually transplant seedlings to larger pots. Fill medium-sized pots about three-quarters of the way up with a moderately fertile potting soil. Remove the seedling from the tray and place in the pot. Fill around the sides with the potting soil and lightly press down so the seedling is firmly in place. Water thoroughly. Keep the plants in a sunny place and the soil well-drained. Water regularly.
Once seedlings are large enough and the risk of frost has passed, gradually move plants outdoors to harden them off. Start by leaving them outdoors in a sheltered place only during the day for about a week. When the weather is suitable, leave them outside at night covered with fleece for a week. Near the end of the third week, leave them uncovered overnight before planting them in the garden.
Seedlings will flower in their third or fourth summer, and divided plants usually do not flower in the first year, according to Agapanthus.org.uk. Plants grown in the garden are easier to divide than those in pots because the roots have more space to spread out. Division reduces flowering on the parent plant. Large clumps should be divided no more than once every 4-6 years, according to the Royal Horticultural Society.