Plant Care Guide

Purple Fountain Grass

Pennisetum setaceum ‘Rubrum’

Red Fountain Grass, also known as Purple Fountain Grass, is one of the most striking ornamental grasses for landscapes and container gardens. With its burgundy-red foliage and graceful arching plumes, it brings texture, color, and movement to gardens from summer into fall. This fast-growing grass is adaptable, heat-tolerant, and makes an excellent low-maintenance focal point.

Watering Requirements

Fountain grass is relatively drought-tolerant once established but performs best with consistent watering during its early growth. Steady moisture encourages lush foliage and showy plumes, but overwatering should be avoided to prevent root rot.

Watering Schedule:

  • Spring/Summer: Water 1–2 times per week until established, then reduce to occasional watering if rainfall is sufficient
  • Fall/Winter: Cut watering back; dormant plants need minimal moisture

Signs of Overwatering: Yellowing leaves, soggy soil, root rot

Signs of Underwatering: Browning leaf tips, dry or crispy foliage

Pro Tips

In hot, dry climates, a deep weekly soak is more effective than frequent shallow watering.

Light Requirements

This ornamental grass thrives in full sun, where its foliage develops the richest burgundy tones and produces the most plumes. It can tolerate light shade, but expect reduced flowering in lower light.

Ideal Placement: South- or west-facing garden beds, borders, or large patio containers

Too Much Light: In extreme afternoon sun, tips may scorch without adequate water

Too Little Light: Sparse foliage, weak growth, and fewer plumes

Pro Tips

For maximum plume production, ensure at least 6–8 hours of direct sunlight daily.

Soil and Potting

Red Fountain Grass is adaptable but prefers well-draining soil with moderate fertility. It does best in loose, loamy mixes that allow water to drain quickly.

Best Soil Mix: Garden loam or potting soil with compost, sand, or perlite

Container Growing: Use a large, sturdy pot with ample drainage holes; repot every 2–3 years if rootbound

Pro Tips

Add a slow-release fertilizer to the potting mix at planting time for strong establishment.

Fertilizing

Although fountain grass tolerates poor soils, fertilization boosts growth and enhances plume production.

Fertilizer Schedule:

  • Spring–Early Fall: Feed monthly with a balanced, slow-release fertilizer
  • Winter: Pause feeding when the plant is dormant

Deficiency Clues: Yellowing leaves, stunted growth, or reduced flowering

Pro Tips

Over-fertilizing can lead to floppy growth; stick with light, consistent feeding.

Pruning and Maintenance

Pruning is key to keeping fountain grass looking its best, as older foliage can become ragged by the end of the season.

  • Pruning Guidelines:

    Cut back clumps to 3–6 inches above the ground in late winter or early spring before new growth begins

    Remove spent plumes and damaged foliage as needed throughout the season
  • Maintenance Notes: Plants are largely pest-free; brush out old leaves after cutting back to improve air circulation

Pro Tips

Tie foliage into a bundle with twine before cutting back—it makes cleanup much easier.

Common Problems and Solutions

Red Fountain Grass is low-maintenance, but certain stressors can cause problems if not addressed.

  • Browning Foliage

    Cause: Underwatering, extreme heat, or excessive fertilizer

    Solution: Water deeply, provide afternoon shade in hot climates, and avoid overfeeding
  • Yellowing Leaves

    Cause: Overwatering or nutrient deficiency

    Solution: Allow soil to dry between waterings; supplement with a nitrogen-based fertilizer if deficiency is suspected
  • Rust Fungus

    Cause: Humidity trapped in dense clumps

    Solution: Thin plants for airflow and avoid overhead watering
  • Sparse Flowering

    Cause: Insufficient sunlight or poor soil fertility

    Solution: Relocate to a sunnier spot and apply balanced fertilizer during summer

Toxicity Warning

Red Fountain Grass is non-toxic to humans and pets, making it safe for households and pollinator-friendly gardens.