What Are Costus Plants – Learn About Growing Costus Crepe Ginger
By: Mary Ellen Ellis
Costus plants are pretty plants related to ginger that produce a stunning flower spike, one per plant. While these plants require a warm climate, they can also be enjoyed in containers that can be brought indoors in the winter in colder climates.
What are Costus Plants?
Costus plants are related to ginger and at one time were classified with them in the Zingiberaceae family. Now they have their own family, Costaceae. These plants are subtropical to tropical and develop from a rhizome that produces one flower on a spike. Costus plants are great for height in the landscape, as they can grow up to 6-10 feet (2-3 meters) tall. They are hardy to zones 7 through 12.
Varieties of Costus
The costus plants come in several varieties. Most common is Costus speciosus, also known as crepe ginger. The name describes the crepe-like, pale pink flowers. Crepe ginger is one of the tallest varieties of costus.
Costus varzeareanum is an interesting addition to the garden. Its purple leaf undersides provide color and interest even when the plant is not flowering. Another variety, Costos productus, grows lower than other types of costus. It also has edible, sweet-tasting flowers.
You will also find many other varieties of costus when searching for crepe ginger and its relatives. There are multiple cultivars as well, which include different colors of flowers, like yellow, chocolate brown, pink, red, orange, and everything in between.
How to Grow Costus Plants
Growing costus crepe ginger and other varieties of this subtropical to tropical plant is not hard if you have the right conditions and costus plant information. These plants need warmth and will not tolerate much frost. They do need to be kept drier in the winter, though. Fertilize and keep them moist in the spring.
All varieties of costus are well suited to partial shade and morning light. With more sun, these plants need more water. Regardless of location, they should be well watered at all times. Soil should be light and needs to drain well.
Pests and diseases are not major issues for costus plants.
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SERIES 17 | Episode 17
Costus speciosus, like the other Costus species is a tropical and subtropical plant with spectacular flower spikes. 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.
Costus grow from a rhizome and each produces a single flower. It's important that the rhizome be kept dry during winter, but in spring, when growth starts, it should be well fertilised and watered.
Although the various Costus species are tropical and subtropical plants, they can be grown outdoors as far south as Sydney in a warmish spot in the garden. Further south it's recommended to grow them in pots under cover, or on a veranda. It's important to find the right spot for them. They like dappled shade because in full sun they can get burnt. In winter cut them down to ground level because they can look a bit ratty.
Costus speciosus is commonly called Crepe Ginger because the pale pink, crepe like flowers are carried on top of red cones or bracts. It's one of the larger growing varieties.
Costus productus is sometimes called Costus comosus and it's actually an edible variety. The flower petals are quite sweet and nutritious. It's a lower grower and makes a great ground cover.
The long red flower spikes of Costus pulverulentus are unique to the family and they're sure to create interest in the garden. It's a medium grower.
Costus varzeareanum has a distinctive purple underside to the leaves, creating year round interest after the flowers have finished.
Costus don't seem to have much of a problem with pests and diseases. Out in the garden they might sometimes be chewed by caterpillars, and indoors they might be affected by red spider mite, but that's about it.
There are at least 90 varieties of Costus from which to choose, so you shouldn't have any trouble finding one for your particular needs. But remember, the size varies between species and cultivar, so do your homework before you go out and shop. A Costus makes a great filler plant for the tropical and subtropical garden, but is also good as a container grown feature plant. I'll guarantee you won't be disappointed.
Costus Species, Red Costus, Spiral Ginger
Tropicals and Tender Perennials
Average Water Needs Water regularly do not overwater
USDA Zone 9a: to -6.6 °C (20 °F)
USDA Zone 9b: to -3.8 °C (25 °F)
USDA Zone 10a: to -1.1 °C (30 °F)
USDA Zone 10b: to 1.7 °C (35 °F)
USDA Zone 11: above 4.5 °C (40 °F)
Where to Grow:
Grow outdoors year-round in hardiness zone
This plant is attractive to bees, butterflies and/or birds
Soil pH requirements:
By dividing rhizomes, tubers, corms or bulbs (including offsets)
This plant is said to grow outdoors in the following regions:
On Mar 22, 2019, HoustonJK from La Porte, TX wrote:
Provides excellent height behind other plantings in partly sunny to shady areas. Foliage is fantastic. Moderately thick leaves spiral to create interest. Very hardy and easy to grow. Fairly rare in gardens. The bloom looks like an orange pine cone that puts out flowers in succession. Not spectacular but paired with the great foliage this is a cool plant to have in semi-challenged areas of a garden.
On Oct 29, 2009, mswestover from Yulee, FL (Zone 9a) wrote:
I purchased some tubers on ebay last spring (08). They quickly took root, grew and bloomed a little by November. This spring I divided the roots and had enough to start another bed. Now both beds have quickly filled up and I have numerous sprouts getting ready to bloom again. The plant is about four foot high. Dies back in winter, mulch with pine straw and it comes right up again. I do not water them in the winter.