Cenchrus setaceus
Cenchrus setaceusUSDA | Grow Zone
9-11Outdoors all year in zones 9 to 11. Anywhere colder, keep it as a houseplant. Protect it below 40°F.
- Light
- Full sun
- Water
- Moderate, every 1-2 weeks
- Humidity
- 40-60%
- Temperature
- 65-85°F (18-29°C)
- Difficulty
- Beginner
- Growth
- Moderate
- Mature size
- 3-5 ft tall, 2-4 ft wide
Cenchrus setaceus, or fountain grass, is a stunning ornamental grass known for its graceful arching form and feathery flower spikes. Native to Africa and the Mediterranean, it adds texture and movement to gardens, making it a popular choice for landscaping.
Ask Vesper about Cenchrus setaceus
Ideal temperature
65-85°F is where it grows fastest. Below 40°F cold damage starts.
Spacing and harvest
- Mature size
- 3-5 ft tall, 2-4 ft wide
- Plant apart
- 24-36 in
- Frost
- Half hardy: light frost only
Everything it needs
9 essentials at a glance
Watering
Cenchrus setaceus, commonly known as fountain grass, prefers to be watered moderately.
Water deeply once every 1-2 weeks, allowing the top inch of soil to dry out between waterings. During hot summer months, you may need to increase frequency. Signs of over-watering include yellowing leaves and root rot, while under-watering may cause browning leaf tips and wilting.
Light
Fountain grass thrives in full sun, requiring at least 6-8 hours of direct sunlight daily.
Ideal placement includes sunny borders or open areas where it can receive ample light. While it can tolerate partial shade, it may not flower as abundantly in lower light conditions.
Soil
This grass prefers well-draining soil with a pH range of 6.0 to 7.0.
A sandy loam or a potting mix designed for ornamental grasses is ideal. Ensure good drainage to prevent waterlogging, which can lead to root issues.
Humidity
Cenchrus setaceus prefers average humidity levels, around 40-60%.
To increase humidity, mist the plant occasionally or place a humidity tray nearby. Signs of humidity stress include browning leaf edges and stunted growth.
Temperature
Fountain grass thrives in temperatures between 65-85°F (18-29°C) and is hardy in USDA zones 9-11.
It can tolerate brief periods of cold but should be protected from frost, as it is not frost-tolerant.
Fertilizing
Use a balanced fertilizer with an NPK ratio of 10-10-10, applying every 4-6 weeks during the growing season.
Reduce fertilization in late summer and fall. Signs of nutrient deficiency include poor growth and yellowing leaves.
Pruning
Prune fountain grass in late winter or early spring before new growth begins.
Use sharp shears to cut back old foliage to about 6 inches above the ground. This encourages new growth and helps maintain a tidy appearance.
Repotting
Repot Cenchrus setaceus every 2-3 years or when it becomes root-bound.
Choose a pot that is 1-2 inches larger in diameter. Signs it needs repotting include roots growing out of the drainage holes and stunted growth. To repot, gently remove the plant from its pot, loosen the roots, and place it in fresh soil.
Propagation
Propagation can be achieved through division or seeds.
For division, carefully separate clumps in spring or fall, ensuring each division has roots. For seed propagation, sow seeds in spring after the last frost, covering lightly with soil and keeping moist until germination.
When it's unhappy
Yellow leaves
Why it happens
Typically caused by over-watering or nutrient deficiency.
How to fix it
Adjust watering schedule and consider fertilizing with a balanced fertilizer.
Browning leaf tips
Why it happens
Often a sign of under-watering or low humidity.
How to fix it
Increase watering frequency and consider misting the plant to raise humidity.
Stunted growth
Why it happens
Can result from poor soil quality or insufficient light.
How to fix it
Ensure the plant is in well-draining soil and receiving adequate sunlight.
Root rot
Why it happens
Caused by over-watering and poor drainage.
How to fix it
Reduce watering, improve drainage, and consider repotting into fresh soil.
Pests (e.g., aphids)
Why it happens
Pests may infest the plant due to environmental stress.
How to fix it
Inspect regularly and treat with insecticidal soap or neem oil as needed.
Care through the year
Spring
In spring, prune back old foliage to encourage new growth. Fertilize with a balanced fertilizer to promote healthy development.
Summer
During summer, ensure consistent watering, especially in hot weather. Monitor for pests and maintain adequate sunlight exposure.
Fall
In fall, reduce watering as the plant enters dormancy. You may also want to cut back the foliage to prepare for winter.
Winter
In winter, protect the plant from frost by covering it if necessary. Avoid watering unless the soil is completely dry.
Toxicity & Safety
Cenchrus setaceus is non-toxic to pets and children. It poses no known health risks upon ingestion.
Good to know
How often should I water my fountain grass?
Water fountain grass every 1-2 weeks, allowing the top inch of soil to dry out between waterings. Adjust frequency during hot weather.
What type of soil is best for Cenchrus setaceus?
Fountain grass prefers well-draining soil with a pH of 6.0 to 7.0. A sandy loam or a specialized potting mix works best.
When should I prune my fountain grass?
Prune fountain grass in late winter or early spring before new growth appears. Cut back old foliage to about 6 inches above the ground.
What are common pests that affect fountain grass?
Common pests include aphids and spider mites. Regularly inspect your plant and treat with insecticidal soap if necessary.
Can I grow fountain grass in partial shade?
While fountain grass can tolerate partial shade, it thrives best in full sun with at least 6-8 hours of direct sunlight daily.
How can I propagate Cenchrus setaceus?
You can propagate fountain grass through division or seeds. Divide clumps in spring or fall, or sow seeds in spring after the last frost.
What should I do if my fountain grass has yellow leaves?
Yellow leaves can indicate over-watering or nutrient deficiency. Adjust your watering schedule and consider applying a balanced fertilizer.
Track this plant in your garden.
Set care reminders, log growth, and join a community of plant lovers.