Agapanthus (Agapanthus africanus)

Six inches clusters of tubular flowers will open gradually over a six week period if you keep your agapanthus in a cool location. Do not overpot-this plants blooms best when roots crowd each other. Peter Pan and Dwarf White are good varieties for containers. Flower stems will reach two feet in height.

Light

Agapanthus like at least half a day of full sun

Water

Keep soil just moist from early spring to September. Let foliage be your guide. If it sags, give more water.

Special helps

In spring and summer only, feed every two weeks with any complete soluble or liquid fertilizer. After flowering, if the pot is completely soluble rootbound, divide the clump of tuberous roots into several portions. Use any general potting mix of average fertility. Agapanthus is virtually pest-free. Old leaves yellow naturally; remove them gently. 

Source : Growing Houseplants