Kaffir lilies (Clivia spp.) are tender bulbs related to amaryllis. Whether grown inside or out, the plants have few problems but are particular about their care. One common problem is yellowing leaves.
Clivias develop yellow leaves and root rot if they are over-watered. They grow best when kept barely moist in pots with excellent drainage. Clivias bloom more freely when their roots are crowded, so don't re-pot until the bulb starts to push out of the container.
New Leaf Production
It's not uncommon for older, outside leaves to yellow as new foliage grows up from the center of the plant. Cut the old foliage off close to the bulb with sharp scissors.
Care During Rest Periods
Clivias normally have two rest periods each year -- the first in winter before flowering and again immediately after their spring blooming period. During the rest periods, water only once every three or four weeks and don't fertilize. Resume weekly watering when new growth appears.