Crepe ginger is a tall and dramatic landscape plant with large dark green leaves arranged on the stalk in a spiral. This Costus can grow to 10 ft (3.1 m) tall in frost-free areas, but typically grows to about 6 ft (1.8 m) tall in cooler regions where it is root hardy but dies back in winter.
The flowers appear in late summer or early fall, and are quite unusual looking. They form on red 4 in (10.2 cm) cone-shaped bracts, with several 2 in (5 cm) pure white crinkled flowers protruding from each cone. The flowers look like crepe paper - thus the common name of crepe ginger. After the flowers fade away, the attractive red cone-shaped bracts remain.
As beautiful as the species is, there are a number of cultivars of Costus speciosus that are sought after as garden ornamentals. Most are not as hardy as the species and do not grow as tall. The cultivar 'Pink Shadow' is similar to the species but the white flowers are blushed with pink. The cultivar 'Variegatus' has green and white variegated leaves, flowers similar to the species, grows to 5-7 ft (1.5-2.1 m), but is only hardy to zone 9. The cultivar 'Foster Variegated' has reddish stems and broad creamy white striped leaves which are soft and furry to the touch. It only grows to 5 ft (1.5 m) tall and is less likely to flower than the species. The cultivar 'Nova' is a shorter plant, to about 3 ft (0.9 m), and has light green foliage and flowers similar to the species. Another short tetraploid is offered by Stokes Tropicals, and the description is similar to 'Nova'.
Costus speciosus is native to the Malay Peninsula of Southeast Asia, but it has naturalized in some tropical areas, including Hawaii. It is listed as a potential invasive plant in the Federated States of Micronesia, Guam, Republic of Palau, and in French Polynesia.
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. Monthly applications of a balanced fertilizer during the summer growing season will benefit this plant. Generally crepe ginger is pest free.
Crepe ginger grows from thick fleshy roots called "rhizomes", similar in appearance to the "ginger root" found in grocery stores. They may be purchased as potted plants or as bare rhizomes, and they are easy to grow either way. Plant the rhizome about 1 in (2.5 cm) below the surface in a sandy loam or clay soil that has been improved with leaf mold or well composted manure. A single rhizome will produce new shoots and increase to a 3 ft wide clump in the second year under ideal growing conditions.
Light: Prefers part sun but will grow in full sun if it gets plenty of moisture.
Moisture: Requires regular moisture but not standing water.
This is the most cold-hardy of the spiral gingers, and has been tested and proven root hardy down to 0ºF (-17.8ºC).
Hardiness: USDA Zones 7 - 12.
The small seeds are slow germinating - up to 8 weeks depending on the soil temperature. Plant at 1/2'' depth using soil mixture. Be sure they are kept warm - 70 F degrees is ideal. Provide bright light and high humidity by covering the pot with a plastic sheet.