Abundant intense blue or purple flowers, tidy growth habit and graceful cascading stems makes trailing lobelia (Lobelia erinus var. pendula) a valuable addition especially suited to container growing or to rock gardens. Native to South Africa, trailing lobelia is a tender perennial that is hardy to U.S. Department of Agriculture hardiness zones 9 through 10. It can be grown as an annual almost anywhere. Trailing varieties include "Light Blue Basket" and "Pendula Sapphire," the latter with white-eyed blue flowers. Traditionally grown from seed, commercial lobelia production is trending to vegetative propagation from cuttings.