Calla lilies are cultivated in containers or grown in a garden. Different varieties have different coloured flowers, but the most common calla lily has white, trumpet-shaped flowers and dark green foliage. Calla lilies grow in any climate, but flowering can be hindered without enough light and care.
Calla lilies grow nice and green in shady areas. However, if the calla lily is to bloom, it needs at least four to five hours of direct sunlight. The afternoon sun may be too hot for the calla lily, but a morning sun or a western sun is ideal.
Fertilising calla lilies once in spring with a 5-10-10 nitrogen-phosphate-potassium fertiliser provides enough potassium and phosphates for promoting blooms and little nitrogen, which promotes more foliage than blooms. Calla lilies need a rich soil provided by fertilising the ground the rhizomes are planted in each spring.
Calla lilies grown in containers and stored indoors for winters never have the rhizomes divided. Calla lilies produce few flowers or no flowers at all when the rhizomes are clumped together. Divide the rhizomes and make more than one plant, and each one flowers during the season.
Water is necessary for flowering calla lilies. Lilies need moist soil to grow and flower. During dry periods, provide at least 2.5 cm (1 inch) of water to the ground around the calla lily keeping the soil moist. Laying down 2.5 to 5 cm (1 or 2 inches) of mulch around the base of the plant helps keep the soil cool and the soil moist longer.
Calla lilies spread out as the rhizomes multiply. When the plants grow together with other plants or shrubs, crowding occurs, as well as a fight for the nutrients in the soil, which will slow down or stop flowering. Calla lilies need room between plants to grow and flower. Plant calla lilies at least 15 cm (6 inches) away from other plants.