Costus guanaiensis, also named Spiral ginger, can grow to 9 feet tall in frost-free areas. It is native to tropical regions of South America. It's related to the gingers and was originally part of the Zingiberaceae family, but now the Costus species have been reclassified into their own family, Costaceae. As with most gingers, this plant is easy to grow with virtually no pest problems.
Spiral ginger is a tall and handsome landscape plant with large green leaves with a yellowish side, up to 20 cm long or more, about 4-6 cm wide, arranged on the stalk in a spiral. It produces spiralling stems of magnificent white, pink and yellow flowers. The flowers appear in late summer or early fall. Costus guanaiensis is distinguished by its green bracts with green leafy appendages and large mostly white spreading flowers. The amount of reddish color in the flowers varies.
Hardiness zones 8-11, (-10§C/15§F, 4§C/40§F) in winter. For best results, this plant should get from 3 to 5 hours of direct sunlight daily, and be grown in fertile, organic, moist but well-drained soil. Requires consistently moist soil; do not let dry out between waterings. Monthly applications of a balanced fertilizer during the summer growing season will benefit this plant.
Spiral ginger grows from thick fleshy roots called rhizomes. A single rhizome will produce new shoots and increase to a 3 feet wide clump in the second year under ideal growing conditions. It's important that the rhizome be kept dry during winter, but in spring, when growth starts, it should be well fertilized and watered.