Light. Grows in full sun or partial shade. Full sun gives the most flowers.
Water. Water regularly while it establishes. Giant crinums grow best in moderately moist soil, so water during dry spells, especially in summer.
Soil and feeding. It grows in sand to clay, acidic to slightly alkaline. Plant the bulb with its neck above the soil. Little or no fertilizer is needed.
Size. Grows to about 4 ft and forms a large clump; space plants 4–6 ft apart in a mass planting.
Pruning. Remove cold-damaged leaves and spent flower stalks.
Problems to watch. Eastern lubber grasshoppers are the main pest; control the young ones in spring. Leaf spots and spider mites sometimes appear.
Good to know. Crinums contain toxic alkaloids and can poison people if eaten. It is moderately tolerant of salt spray away from direct salt spray.
Sources: UF/IFAS Gardening Solutions: Crinum Lilies · UF/IFAS Extension Duval County: Crinum season · UF/IFAS EDIS: Crinum x amabile, Giant Spider Lily · Chicago Botanic Garden: Crinum augustum 'Queen Emma'
