Plant African irises 2 to 3 feet apart in a sunny space. Water the plants regularly, and fertilize them in March, June and August. Prune and weed African irises regularly, and check for and treat nematode infestations as needed.
African irises need six to eight hours of full sunlight each day and about an inch of water per week. These flowers are particularly susceptible to nematode infestation, which can cause leaf damage and discoloration and root swellings. To prevent infestation, buy nematode-free plants, and heat the soil to 125 degrees Fahrenheit for at least 30 minutes prior to planting. Weed the soil around the plants regularly, and add 2 inches of mulch a few inches away from the base of the plants to prevent weed growth.