Large, blue, palm-shaped flowers make the agapanthus a striking addition to a perennial garden. Planted en masse in the landscape, agapanthus creates a sea of blue against a backdrop of bright green sword-shaped leaves. This perennial bulbous plant grows best in full sun and deep rich soil. Divide agapanthus every four to six years in early spring or late fall when the plant is not in bloom. Dividing and replanting agapanthus is an easy but necessary part of growing large healthy plants.
Place a garden fork about 3 to 5 inches from the base of the agapanthus clump and drive it into the soil. Pull back on the handle of the garden fork to lift the clump of rhizomes from the soil.
Brush off the soil from around the bulbs and gently pull the rhizomes apart. Separate out any that look rotted, diseased or dried out.
Place the rhizomes out in the new planting area. Space multiple plants about 12 to 18 inches apart. Select a spot that gets full sun and that has well-draining loamy soil.
Plant the rhizomes under about 2 inches of soil the same way as they were in their original spot. Pat down the soil around the planting area gently and soak the soil until it is damp to about 4 inches deep.