Uruguayan Pampas Grass
Cortaderia selloana
Cortaderia selloana, commonly known as Pampas Grass, is a striking ornamental grass native to South America. Known for its tall, feathery plumes, it adds dramatic flair to gardens and landscapes, making it a popular choice for gardeners seeking a bold statement.
Everything it needs
9 essentials at a glance
Watering
Cortaderia selloana prefers well-drained soil and should be watered deeply but infrequently.
Water every 2-3 weeks during the growing season, allowing the top inch of soil to dry out between waterings. In winter, reduce watering to once a month. Signs of over-watering include yellowing leaves and root rot, while under-watering may cause browning leaf tips and wilting.
Light
This plant thrives in full sun, requiring at least 6-8 hours of direct sunlight daily.
Ideal placement is in an open area where it can receive unobstructed light. While it can tolerate partial shade, reduced sunlight may lead to weaker growth and fewer flower plumes.
Soil
Cortaderia selloana prefers sandy or loamy soil with a pH range of 6.0 to 7.5.
The soil should be well-draining to prevent waterlogging. A recommended potting mix would be a blend of potting soil, sand, and perlite to enhance drainage.
Humidity
This grass prefers moderate humidity levels but is quite adaptable.
To increase humidity, mist the leaves or place a humidifier nearby. Signs of humidity stress include browning leaf edges and stunted growth. If humidity is too high, it may lead to fungal issues.
Temperature
Cortaderia selloana thrives in temperatures between 60-85°F (15-29°C) and is hardy in zones 7-11.
It can tolerate brief periods of cold down to 20°F (-6°C) but should be protected from frost. In extreme heat, ensure adequate watering to prevent stress.
Fertilizing
Use a balanced fertilizer with an NPK ratio of 10-10-10 or similar.
Fertilize every 4-6 weeks during the growing season, tapering off in late summer. Signs of nutrient deficiency include yellowing leaves and poor growth. If this occurs, consider a slow-release fertilizer to boost nutrient levels.
Pruning
Prune in late winter or early spring before new growth begins.
Use sharp, clean shears to remove dead foliage and spent flower plumes. This will encourage fresh growth and maintain a tidy appearance. Deadheading is not necessary but can improve aesthetics.
Repotting
Repot every 2-3 years or when the plant becomes root-bound.
Choose a pot that is 1-2 inches larger in diameter. Signs that it needs repotting include roots growing out of the drainage holes and stunted growth. When repotting, gently loosen the roots and place in fresh potting mix.
Propagation
Propagation is best done through division in spring or early fall.
Carefully dig up the clumps, ensuring each division has roots and healthy foliage. Replant in well-draining soil at the same depth as before. Alternatively, seeds can be sown in spring after the last frost, but this method may take longer to establish.
When it's unhappy
Yellowing leaves
Why it happens
Typically caused by over-watering or nutrient deficiency.
How to fix it
Reduce watering frequency and check soil drainage. Apply a balanced fertilizer if nutrient deficiency is suspected.
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 or using a humidifier.
Root rot
Why it happens
Caused by excessive moisture in the soil.
How to fix it
Ensure proper drainage and reduce watering. If root rot is severe, consider repotting into fresh, dry soil.
Pests (e.g., aphids, spider mites)
Why it happens
Can occur in dry conditions or when plants are stressed.
How to fix it
Inspect regularly and treat with insecticidal soap or neem oil if pests are found.
Fungal diseases
Why it happens
High humidity and poor air circulation can lead to fungal issues.
How to fix it
Ensure good air circulation, avoid overhead watering, and apply a fungicide if necessary.
Care through the year
Spring
In spring, prune back any dead foliage from the previous year and begin a regular watering schedule as new growth emerges.
Summer
During summer, ensure consistent watering, especially in hot weather, and consider applying a balanced fertilizer every 4-6 weeks.
Fall
In fall, reduce watering as temperatures cool and prepare the plant for winter by cutting back any dead or damaged foliage.
Winter
In winter, limit watering to once a month and protect the plant from frost by covering it if temperatures drop significantly.
Toxicity & Safety
Cortaderia selloana is considered non-toxic to pets and children. However, the sharp edges of the leaves can cause minor skin irritation or injury if handled carelessly.
Good to know
How often should I water my Pampas Grass?
Water your Pampas Grass every 2-3 weeks during the growing season, allowing the top inch of soil to dry out between waterings.
Why are my Pampas Grass leaves turning yellow?
Yellowing leaves can be a sign of over-watering or nutrient deficiency. Check your watering schedule and consider fertilizing if needed.
What type of soil is best for Pampas Grass?
Pampas Grass thrives in sandy or loamy soil with good drainage and a pH range of 6.0 to 7.5.
How can I propagate Pampas Grass?
You can propagate Pampas Grass by division in spring or early fall. Ensure each division has roots and healthy foliage before replanting.
What is the ideal temperature for Pampas Grass?
Pampas Grass prefers temperatures between 60-85°F (15-29°C) and is hardy in zones 7-11.
How do I prune Pampas Grass?
Prune Pampas Grass in late winter or early spring by removing dead foliage and spent flower plumes with sharp shears.
Is Pampas Grass toxic to pets?
No, Pampas Grass is non-toxic to pets and children, but the sharp edges of the leaves can cause minor skin irritation.
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