How to Plant, Grow, and Care for Purple Fountain Grass
A versatile accent that brings dynamic color and movement to gardens with minimal effort.
Looking for a low-maintenance, dazzling ornamental grass to add dynamic color and movement to your garden? Purple fountain grass (Pennisetum setaceum âRubrumâ), prized for its arching burgundy foliage and bottlebrush plumes, transforms any landscape with striking texture and seasonal interest. In this comprehensive guide, discover how to choose, plant, grow, and maintain vibrant purple fountain grass from selection to stunning design combos.
Purple Fountain Grass Overview
Purple fountain grass is a popular ornamental known for its elegant, fountain-like mounds of arching foliage in rich burgundy-purple tones and its soft, feathery flower spikes. Native to Africa and southwestern Asia, this fast-growing grass is ideally suited to USDA zones 9-11 and grown as an annual in cooler regions.
| Feature | Details |
|---|---|
| Botanical Name | Pennisetum setaceum âRubrumâ (Cenchrus setaceus cultivars) |
| Common Name | Purple fountain grass |
| Zones | 9â11 (annual in colder climates) |
| Height x Spread | 3â5 ft tall x 2â4 ft wide |
| Sun Exposure | Full sun to partial shade |
| Soil Type | Average, well-drained |
| Bloom Time | JulyâOctober |
Distinctive Characteristics
- Foliage: Arching, narrow, and sword-like with a rough surface, colored deep purple, red, or bronze. Leaves are long (1â3 feet), hold color all season, and do not wilt easily.
- Plumes: Feathery, bottlebrush-shaped spikes in shades from pink and cream to burgundy-red appear late summer through early autumn. The flower stalks rise above the foliage and bend gracefully outward.
- Seedheads: Plumes mature to produce seeds that birds may feed on. The seeds can self-spread in favorable conditions.
- Texture & Form: Forms symmetrical, wide-spreading mounds, offering draping movement and contrast in mixed plantings.
Is Purple Fountain Grass Invasive?
Some fountain grass species, especially wild Pennisetum setaceum, are considered invasive in parts of the southern U.S. and California because their seeds disperse and crowd out native plants.
However, the âRubrumâ cultivar typically sold as purple fountain grass is generally sterile and not invasive, though caution is wise in sensitive regions. Check with your local extension office or agricultural authority before planting if youâre in a wildfire-prone or invasive species-sensitive area.
Where to Plant Purple Fountain Grass
- Plant in a spot with full sun (6+ hours/day) for deepest foliage color. Some partial shade is tolerated but may soften the purple hues.
- Soil should be well-drained. Fountain grass adapts to many soil types (sandy, loamy, even slightly clayey), but consistently wet soil will cause root rot.
- Space clumps 2â4 feet apart to allow mature mounds to develop their arching form.
- Many gardeners grow purple fountain grass in containersâperfect for patios, poolside, or accenting borders.
How to Plant Purple Fountain Grass
- When to Plant: Plant outdoors after the last frost date, once soil has warmed. In frost-free areas, spring or early fall is ideal, allowing at least a month before the first expected frost for roots to establish.
- Prepare the Site: Loosen soil to about 8â10 inches deep. Amend with organic compost for nutrition if your soil is poor.
- Planting: Dig a hole twice as wide as the rootball but no deeper. Place the plant so the top of the root ball is level with the surrounding soil. Backfill and tamp lightly.
- Watering In: Water deeply after transplanting to help roots settle. Maintain even moisture until signs of new growth appear.
What others are reading
Growing in Containers
- Use a sturdy pot (at least 16â20 inches across) with ample drainage holes.
- Fill with good-quality, well-draining potting mix.
- Water regularly, as containers dry out faster than garden beds.
- Pair with trailing annuals or bright perennials for a lush statement on decks, patios, or entryways.
Watering Requirements
- Drought Tolerance: Once established, fountain grass is fairly drought tolerant. However, regular waters keep it lush and promote vibrant growth.
- Soak soil thoroughly and allow the top inch to dry between waterings for garden-grown plants; container plants need water more frequently in hot weather.
- Too little water may lead to browning or reduced flowering; overwatering or poorly drained soil can cause root rot.
Fertilization
- In average garden soil, purple fountain grass requires little supplemental fertilizer.
- Top-dress with an all-purpose slow-release fertilizer in early spring, especially in containers or nutrient-poor soils.
- Overfertilizing can encourage floppy growthâalways follow label rates.
Ongoing Maintenance
- Pruning: In frost-free regions where fountain grass is perennial, cut plants back hard in late winter or early spring before new shoots emergeâleave 3â4 inches above the crown. This rejuvenates foliage and triggers dense new growth. In cold climates, remove frost-killed foliage in spring.
- Division: Every 2â3 years, dig up mature clumps in early spring and divide for additional plants. Use a sharp spade or saw for large, woody masses. Discard any dead centers, and replant outer growth.
- Pest and Disease Control: Purple fountain grass is largely pest- and disease-resistant. Watch for root rot in excessive moisture.
- Winter Care (in cold zones): Grown as an annual where winters dip below freezing, or bring potted plants indoors or to a sheltered garage over winter. Trim leaves and store cool and dry, watering lightly every few weeks.
Landscape Design Ideas
Purple fountain grass is a favorite choice for adding color, movement, and structure in many landscape styles.
- As a Specimen: Use single plants as focal points surrounded by low groundcovers or gravel for dramatic effect.
- Mass Plantings: Group three or more for a bold sweep of color and texture. Excellent lining walkways or around patios.
- Companion Plants: Combine with gold, orange, or silver-leaved annuals/perennials for contrast. Favorites include black-eyed Susan, blanket flower, lantana, sedum, and purple salvia.
- Containers: Use as a thriller plant in large pots paired with trailing vinca, sweet potato vine, or calibrachoa.
- Cut Flower Gardens: Flower spikes dry well for floral arrangements.
Propagation
- Best method: division. In early spring, lift mature clumps, split into three or more parts, and replant immediately.
- Division produces identical plants quickly and invigorates aging specimens.
- Seed propagation is possible if fertile cultivars are available, but âRubrumâ is typically sterile.
Common Problems and Troubleshooting
- Browning Foliage: Often due to underwatering, extreme cold, or poor drainage. Snip away damaged leaves and adjust care.
- Floppy Growth: Results from too little sun or excess nitrogen. Move to a sunnier spot and avoid high-nitrogen feeds.
- No Blooms: Usually from shade or juvenile plants. Mature, well-sunned plants bloom reliably.
- Invasiveness: While âRubrumâ rarely self-seeds aggressively, monitor and remove stray seedlings, especially near wild areas or in climates where fountain grass is invasive.
Fire Safety Consideration
All fountain grasses become extremely flammable once dry and dormant, making them a fire hazard in wildfire-prone regions. Do not plant near structures or in wildland-urban interface areas prone to wildfire. Routinely remove dried foliage and prune in late winter to minimize risk.
Frequently Asked Questions (FAQs)
Q: Is Purple Fountain Grass Perennial or Annual?
A: It is a perennial in USDA zones 9-11, surviving mild winters. In colder climates it is grown as an annual, as it is not frost hardy.
Q: How Tall Does Purple Fountain Grass Get?
A: Mature plants grow between 3 and 5 feet tall and up to 4 feet wide, depending on conditions and variety.
Q: Does Purple Fountain Grass Reseed or Spread?
A: Most ornamental cultivars, especially ‘Rubrum,’ are sterile and donât self-sow significantly. However, check local advisories regarding potential spread in sensitive regions.
Q: Can I Grow Purple Fountain Grass Indoors?
A: Mature size and sun needs make it best suited to outdoor settings. Small container specimens may overwinter in a bright, cool, frost-free indoor location with reduced water.
Q: When and How Should I Prune?
A: Prune back hard in late winter or very early spring before new growth. Cut down to 3-4 inches above the crown; this refreshes the plant for the new growing season.
Q: Is Purple Fountain Grass Toxic?
A: Purple fountain grass is non-toxic to humans and pets, making it a safe choice for family and pet-friendly gardens.
Summary
Purple fountain grass is a vibrant, versatile accent plant for gardens, patios, and landscapes looking for easy care and all-season color. Plant it in full sun, use well-drained soil, and irrigate consistently for best results. Whether you cultivate it in a border, a focal container, or mass plantings, this ornamental grass rewards with months of beautiful movement, bold color, and minimal fuss.
References
- https://www.gardendesign.com/ornamental-grasses/purple-fountain.html
- https://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/purple-fountain-grass/
- https://www.epicgardening.com/purple-fountain-grass/
- https://www.youtube.com/watch?v=gZ-Kli_Xooo
- https://www.cnps.org/life-with-plants/why-the-fountain-grass-must-go-3105
Similar Articles
Read full bio of medha deb
