Costus is a plant genus that belongs to the Costaceae family and the Zingiberales order. These tropical herbaceous plants have flowers that spiral on stems that look like bamboo. This stem differentiates it from its relative, the zingiber, or true ginger. In light of their specially marked stems, these plants are often referred to as the spiral gingers.
There are more than 100 species of the Costus, which makes it the largest genus in the Costaceae family. The different species have varying flowers, leaves, and bracts. There are some varieties with flowers and bracts that look like cones, while others are shaped like pineapple or soft crepe coming out of green cones. Some leaves have furry or velvety textures on the back, while others are smooth and purplish.
One of the most popular species in this genus is Costus barbatus, which grows in Costa Rica and has flowers that can last more than a month. Its bract looks like a red pineapple with tiny vibrant yellow flowers peeping out. This species is commonly known as red tower ginger. One other interesting but endangered species grown in Costa Rica is Costus stenophylus, or as it is more commonly known, red snake ginger. It has a brown and tan barber-pole designed main stalk and a red bract with yellow flowers peeking out that resemble a snake’s tongue.
The Costus are native to Asia, and Africa, as well as both American continents. They thrive in partial sun during cold weather and partial shade during sunny weather. Extreme exposure to the sun should be avoided, as they can get burned. These plants are easy to grow in soil that drains well. During winter they should be kept dry. In spring or summer they should be kept fertilized and frequently watered so that their soil is always moist.
These plants grow from rhizomes and are very hardy. They are fairly resistant to pests and diseases. However, caterpillars occasionally feed on them when they are grown outdoors. If the plant is kept indoors, the red spider mite may attack it.
Other than being decorative plants suitable for both the indoors and outdoors, some species of Costus can be used for medical purposes. The Costus speciosus, or crepe ginger, with its distinctive light pink crepe-like flowers, is utilized as a source of diosgenin. This is a compound that can be used to produce different steroids, such as progesterone. Costus scaber is mixed with berries and used as a snake poison antidote for bitten dogs on the Trinidad and Tobago islands.