For Agapanthus to flower well a warm and sunny spot in the garden is required. Flowering may be poor if plants are not given sufficient water, nutrients or sunlight during the growing season.
New flower buds are initiated soon after flowering has finished and may abort in drought conditions, so keep well watered in autumn.
Many Agapanthus prefer to grow in rich, well drained soils, so mulching and supplementary feeding with a high potash feed are often necessary.
Too much shade can lead to lush foliage at the expense of flowering in evergreen species and poor growth in deciduous plants.
Dividing plants will lead to a reduction in flowering. Most plants will only need dividing every four to six years or once flowering begins to deteriorate. Setting seed does not appear to reduce flowering in the following year.
Container plants should be kept in a cool, bright position over winter, avoiding excessive winter wet, or drying out completely. Too much winter warmth may lead to early flowering, but the flower quality will be poor. Plants in containers need additional care with watering as they are more prone to drying out.
Generally, deciduous species are fairly cold-tolerant, but the crowns require some protection in cold weather. Most evergreen species are tender in cold districts, where they are best grown in containers. In the mild southwest of England, these may be grown in borders. Mulch around the crowns in autumn with a layer of bracken, straw or sand 15–22cm deep, removing it in spring before growth begins. The foliage of evergreen species and cultivars may be killed by frost, even in mild areas, but large, well-established plants usually regrow in spring, particularly if mulched.