Agapanthus is a group of 10 species of flowering plants. Agapanthus are herbaceous perennials, which means the plants have succulent green stems and live in excess of two years. The flowers of the Agapanthus genus are funnel-shaped and tend to grow in large, round clusters at the end of thick stems measuring from 2 feet (0.6 m) to 4 feet (1.2 m). The flowers come in a range of shades of blue, white, lilac, pink and violet. Common names for Agapanthus varieties include Lily of the Nile, African Blue Lily and African Lily.
Agapanthus species are native to South Africa from the Western Cape to the Eastern Cape. The plants prefer shaded areas that offer some protection from the hot sun in their natural habitat, but these species thrive in cooler climates in sunny environments with well-drained, moisture-retaining, fertile soil and can also be grown in containers.
Agapanthus are popular with gardeners for the vibrant showy flowers the species produce in summer. If too much shade is given in cooler climates, the plant will produce masses of foliage but will fail to produce many flowers. To improve the performance and production of the plants, fertilizer can be added weekly or fortnightly during the growing season. Fertilizer should not be added after flowers form and begin to show color. Agapanthus varieties should be watered regularly during the growing season in dry areas but should be watered only sparingly during the winter months.
Some species of Agapanthus are evergreen, meaning they retain foliage throughout the year; others are deciduous, meaning the leaves die back at the end of the growing season. Hardiness ranges from half-hardy to fully hardy. Evergreen varieties are usually considered to be the most tender, and some need protection during very cold periods.
Horticultural fleece provides excellent winter protection for more tender, half-hardy varieties. An alternative to fleece is to place a deep layer of sand or straw mulch tightly around the plants in late autumn. Horticulturalists recommend a layer of mulch 6 inches (15 cm) to 9 inches (22 cm) deep. The mulch should be removed in the spring before new growth begins.
Agapanthus varieties are poisonous if consumed. The severity and level of toxicity depends on the amount of plant matter ingested and the body weight of the person who has consumed it. The sap can cause irritation of the skin, so hands should be washed immediately after coming into contact with the sap. Severe mouth pain and ulcerations can occur if the plant is eaten and, if the sap comes into contact with the eye, it may cause severe pain and discomfort.