If your beautiful plant is very ginger-like, it still may not be a ginger plant! If you want to create a tropical garden or indoor plantscape, ginger plants, with their vivid blooms, unique shapes, and lush foliage will do the trick! But sometimes all is not what it seems.
The plant you are looking at might be a costus plant, often known as ‘spiral ginger’ which only confuses the issue.
What is the difference? And when do we care?
The Costus plant is often associated with the ginger family, but it’s technically part of the Costaceae family, which is closely related to the Zingiberaceae family that true gingers belong to.
‘Close but no cigar’, as the old saying goes. (Why, you may ask. Don’t bother, I looked it up.) It means almost, but not quite a win. It comes from the days when a cigar was given to a prize winner. They are called spiral gingers due to their spiral growth pattern, which can make them look similar to gingers.
What Makes A Costus not a Ginger!
- The Leaf Arrangement: Costus leaves are arranged in a single row that spirals around the stem, while ginger leaves are alternately arranged on the stem. In ginger it is the sheath that spirals. (See it really is all in the details.)
- The Flowers: Costus flowers grow in cone-shaped clusters with colorful bracts, while ginger flowers appear in dense cone-shaped spikes.
- No Aromatic oils: Costus plants do not produce the aromatic oils, that we have come to expect from ginger and use in cooking. You won’t get that scent from the costus.
- No Edible Roots: Costus plants do not produce the delicious edible root we use in many kinds of cooking.
Despite the botanical difference, the costus plants share many visual and maintenance similarities with true gingers, making them a popular choice for tropical gardens. So, while they aren’t true gingers, they are certainly close relatives and just as striking in the garden and, indoors, on the plant shelf. But no tasty ginger root!
Where Did We Get The Costus and Ginger Plants
Costus is a genus of herbaceous perennial plants in the family Costaceae, erected by Linnaeus in 1753. It is widespread through tropical and subtropical regions of Asia, Africa, and the Americas. It has been long valued for medicinal purposes.
Ginger is native to parts of Asia including Japan and China. It grows best in hot and humid conditions with lots of nutrients, and temperatures between 18–25°C. We have Marco Polo to thank for ginger. Oddly we don’t see the plant in wild places but it has been used for health and disease management throughout time. So our use of the two plants is very old.
You will find multiple choices of beautiful ginger plants as well as costus. In our tropical garden, we love them all, but they’re all different. Here are some of the costus cousins you can grow indoors or out.
The hardiness zones for costus plants can range from 9-11, but the individual varieties will vary for growing outdoors.
Crape Ginger-Costus speciosis
The white, or pink, white and yellow blooms appear on top of cone-like heads at the tips of the branches.
We have several of these in containers, on covered porches or lightly shaded areas. Make sure to give them regular water and keep them neatly pruned. Left alone the tips turn brow and a little pruning solves the problem. We feed them with a liquid fertilizer, weekly with the annuals. That seems to be all they need.
(Photo Credits: Wikkimedia Commons Images)
Spiral Flag or Fiery Costus-Costus igneus
This one shares the thin leaf and papery blossom but comes in a brilliant orange color.
Red Button Ginger–Costus woodsonii:
A smaller plant with bright red bracts and orange-yellow flowers. The plant is compact at about 24-36″ tall.
Appearance: This perennial plant has glossy, hairless, elliptical leaves that spiral up thick stems. It produces bright red bracts and orange-yellow flowers that bloom from late winter to early spring.
Growing conditions: The plant prefers rich, moist soil in semi-shade, but can tolerate full shade. It should be watered regularly to keep the soil evenly moist.
Uses: Add to tropical gardens, patios, and indoor living spaces. It can be grown in containers, borders, or coastal gardens.
Red Tower Ginger-Costus comosus
Size: It can grow up to six feet tall.
Flowers: It produces bright yellow flowers and overlapping red bracts that bloom almost year-round.
Leaves: It has fuzzy leaves that spiral around its stems.
Uses: It can be used as a cut flower or grown in pots for patios and verandas.
Growing conditions: It prefers full sun to part shade and does well in water-wise gardens. (In older directories you may see this called Costus barbatus.)
Some Costus to Grow Indoors
These are small plants that are known to work indoors.
Costus erythrophyllus
Costus erythrophyllus: This plant is easy to care for and can purify indoor toxins and pollutants. It can be placed on desks, dining tables, balconies, or in hanging pots.
As you see in this photo taken in Germany, i t makes a pretty groundcover too.
Costus arabicus ‘Variegata’
Costus arabicus ‘Variegata’This plant prefers full or partial shade, and needs water twice a week and plant food twice a month. It has attractive, lush leaves with beautiful colors. You won’t often see this coloration!
Why do we write the botanical names this way? The name is in two words. The capitalized first word is the Genus the second word (not capitalized) is the species. ‘The following word’ with single quotes but not in italics is the man-made cultivar. If it were a naturally occurring variety it would have no quotation marks.
So the name can tell you a lot! Here is more information on how to read the names. Latin for Gardeners.(Using the proper name will ensure that you get the plant you wanted when you are buying plants.)
Care and Maintenance of Your Costus Plant
The location and management practice you use for your costus plant will work as well for ginger plants. We use a large shell ginger at thee edge of our rear garden. It is lightly shaded by some palms, and plumeria and it’s dense, high foliage creates a privacy wall.
In a Warm Climate Garden:
1. Planting Location:
- Choose a spot with partial shade to full shade. Morning sun is fine, but too much direct sunlight can scorch the leaves. In our zone 10, South Florida garden we will use a lightly shaded location.
2. Soil to Plant In:
- Plant in rich, well-draining soil. Amend the soil with compost or organic matter to improve fertility and drainage.
3. Watering:
- Keep the soil consistently moist, especially during the growing season. Water deeply once or twice a week, depending on weather conditions. Avoid standing water which will damage the roots.
4. Mulch:
- Apply a layer of mulch around the base to retain moisture, suppress weeds, and regulate soil temperature.
5. Fertilizing:
- Use a balanced, slow-release fertilizer every 4-6 weeks during the growing season to promote healthy growth.
6. Pruning:
- Remove dead or yellowing leaves to keep the plant tidy and encourage new growth. Prune spent flower stalks after blooming.
7. Pests and Diseases:
- Watch out for common pests like aphids and spider mites. Use organic insecticides or neem oil if needed. Ensure good air circulation to prevent fungal diseases.
As a Houseplant:
1. Light:
- Place the Costus plant in a spot with bright, indirect light. Avoid direct sunlight, which can burn the leaves.
2. Soil:
- Use a well-draining potting mix. A combination of potting soil, peat moss, and perlite works well.
3. Watering:
- Keep the soil consistently moist but not soggy. Water thoroughly when the top inch of soil feels dry. Reduce watering in the winter when the plant is not actively growing.
4. Humidity:
- Costus plants thrive in high humidity. Increase humidity by misting the plant regularly or placing a humidifier nearby.
5. Fertilizing:
- Feed with a balanced, liquid fertilizer every 4-6 weeks during the growing season. Reduce feeding in the winter.
6. Pruning:
- Trim dead or yellowing leaves to maintain the plant’s appearance. Remove spent flowers to encourage new blooms.
7. Repotting:
- Repot every 2-3 years in the spring, using fresh potting mix. Choose a slightly larger pot to accommodate growth.
Additional Tips for Both Settings:
- Temperature: Costus plants prefer warm temperatures between 60°F and 80°F (15°C to 27°C). Protect them from cold drafts and sudden temperature changes.
- Propagation: Costus plants can be propagated through division or stem cuttings. Divide rhizomes in the spring or take stem cuttings with a few leaves and root them in water or moist soil.
Summary,
By following these care guidelines, your Costus plant will thrive, whether it’s growing in your garden or brightening up your home. Enjoy the lush foliage and unique spiral growth!
The early plant hunters and botanists made these plant drawings because they thought future gardeners like us would appreciate them.
To quickly review, Costus plants, commonly known as Spiral Gingers, belong to the Costaceae family and are often mistaken for true gingers from the Zingiberaceae family. While they share visual similarities, Costus plants are distinct due to their spiral growth pattern and unique flower structures. Some more popular varieties to grow include Crepe Ginger (Costus speciosus), known for its pale pink, crepe-like flowers; Red Button Ginger (Costus woodsonii ‘Dwarf French Kiss’), with vibrant orange-red flowers; and Red Tower Ginger (Costus comosus var. bakeri), featuring bright red blooms. These varieties thrive in warm, humid climates and can add a touch of the exotic to any garden.
To maintain your costus plants, ensure they are planted in well-draining, fertile soil with partial to full shade. Consistently moist soil is key, so regular watering is essential, especially during dry periods. Mulching helps retain moisture and regulate soil temperature. Fertilize every 4-6 weeks with a balanced, slow-release fertilizer to promote healthy growth. Prune dead or yellowing leaves and spent flower stalks to keep the plant tidy and encourage new growth. With proper care, costus plants can flourish, providing lush foliage and vibrant flowers that add a tropical feel to both gardens and indoor spaces.
As always, Happy Digging!