Costus barbatus or spiral ginger has striking red and yellow torch-shaped inflorescences.
The original habitat is now largely urbanized or cultivated and the plant has become nearly extinct. It has recently been found in a single place in a remaining piece of forest.
Although it is seriously threatened by habitat loss, it is not protected.
It is not found in cultivation, only in botanical gardens.
The plant sold in Costus barbatus is actually Costus comosus var. bakery, to which it resembles strongly. It can also be confused with Costus curvibracteatus.
Although known as spiral ginger, it is not a ginger but belongs to the family Costaceae and not Zingiberaceae. In Costaceae, the inflorescence appears at the top of the stem, in Zingiberaceae from the rhizome.
Costus barbatus is a tall ginger-like herb with spiraling foliage to 2.4 m high.
The stems spiral like a corkscrew.
The elliptic leaves spiral around the stem. They are dark green, 30 cm long and 10 cm wide, with a light green velvety underside.
The terminal inflorescence is torch shaped with red bracts. Striking yellow tubular corollas emerge sequentially from between the bracts. The flowers are short lived but the bracts are very long lasting.
Costus: of the Sanskrit name for the genus: kushtha
Barbatus: Latin barbātus (bearded, woolly, fuzzy)
Along rivers or in wet forest
USDA zone 11
Nutritious, moist and well drained
Partial shade, shade
Monthly general fertilizer during growing season
Heated greenhouse, temperature at least 15 °C all year round.