Jupiter's Beard vs Purple Fountain Grass Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Jupiter's Beard
Centranthus ruber
Centranthus ruber, commonly known as Jupiter's Beard, is a perennial plant typically grown outdoors for its vibrant clusters of small, star-shaped flowers. It forms a bushy clump of grey-green leaves and can reach up to 3 feet in height. The flowers are most commonly a deep rose-red, but can also be white or pink. While visually appealing, it is primarily an outdoor plant and may struggle to thrive indoors due to its high light requirements and potential for aggressive spreading via self-seeding.
Purple Fountain Grass
Pennisetum setaceum 'Rubrum'
Purple Fountain Grass is a striking ornamental grass prized for its arching, burgundy-purple foliage and bottlebrush-like flower plumes. It typically grows in a mounded form, reaching several feet in height and width. While technically a perennial in warmer climates, it is often grown as an annual in cooler regions due to its sensitivity to frost. It is primarily an outdoor plant, grown for its dramatic texture and color in gardens and landscapes. People grow it for its ornamental value, adding movement and visual interest to borders, containers, and mass plantings.
Quick Plant Comparison
| Feature | Jupiter's Beard | Purple Fountain Grass |
|---|---|---|
| Light | Full sun (at least 6 hours of direct sunlight daily) | Full sun (at least 6 hours of direct sunlight per day) |
| Watering | Every 1-2 weeks, depending on weather and soil drainage | Every 7-10 days, depending on weather and soil drainage |
| Humidity | 30-50% | 20-50% |
| Temperature | 15-25°C | 18-30°C |
| Care Level | Expert | Expert |
| Growth Rate | Fast | Moderate |
| Max Height | N/A (Primarily outdoor plant, difficult to maintain indoors) | Outdoor: 0.6-1.5 meters. Indoor (unlikely to thrive): 0.3-0.6 meters |
| Pet Safety | ❌ Toxic To Pets | ✅ Safe |
| Soil | Well-draining soil, such as a sandy loam | Well-draining soil, such as a sandy loam or a potting mix amended with perlite |
| Beginner Friendly | ❌ No | ❌ No |
| Weekly Maintenance | 15 minutes weekly (deadheading, watering) | 15 minutes weekly |
🔬 Botanical Information — Comparing These Plants
Jupiter's Beard
| Scientific Name | Centranthus ruber |
|---|---|
| Family | Caprifoliaceae |
| Native To | Mediterranean region |
| Also Known As | Red Valerian, Spur Valerian, Kiss-me-quick |
| Leaves | The leaves are lance-shaped, grey-green in color, and arranged oppositely along the stems. They are typically 2-4 inches long and have a smooth texture. |
| Flowers | Jupiter's Beard produces clusters of small, star-shaped flowers in shades of rose-red, pink, or white. The flowers bloom profusely from late spring to fall, providing long-lasting color in the garden. It is highly unlikely to flower indoors. |
Purple Fountain Grass
| Scientific Name | Pennisetum setaceum 'Rubrum' |
|---|---|
| Family | Poaceae |
| Native To | Hybrid cultivar; species native to Africa, Southwest Asia |
| Also Known As | Purple Fountain Grass, Red Fountain Grass |
| Leaves | The leaves are long, narrow, and arching, with a deep burgundy-purple color. They have a fine texture and create a graceful, flowing appearance. |
| Flowers | It produces bottlebrush-like flower plumes that are initially a deep burgundy-purple, fading to a tan color as they mature. Flowering typically occurs in summer and fall. It is unlikely to flower indoors. |
📏 Size & Growth — Plant Comparison
Jupiter's Beard
Purple Fountain Grass
🌱 Propagation — Comparing Plant Growth
Jupiter's Beard
Methods: Seed, stem cuttings, division
Difficulty: Easy
Tips: Sow seeds directly in the garden in spring or fall. Take stem cuttings in spring or summer and root them in water or soil. Divide established clumps in spring or fall.
Purple Fountain Grass
Methods: Seed, Division
Difficulty: Moderate
Tips: Divide clumps in spring or early summer. Sow seeds indoors 6-8 weeks before the last frost.
✨ Benefits & Features — Comparing Plant Value
Jupiter's Beard
Jupiter's Beard is known for its drought tolerance and ability to thrive in poor soil conditions. Its vibrant flowers attract butterflies and bees, making it a valuable addition to pollinator gardens. However, its aggressive self-seeding can make it invasive in some areas.
- ✓ Attracts pollinators to the garden
- ✓ Provides long-lasting color in the landscape
- ✓ Drought-tolerant, reducing water consumption
- ✓ Deer-resistant, protecting your garden from damage
- ✓ Low-maintenance, saving time and effort
- ⚠️ Toxic to pets
Purple Fountain Grass
Its deep purple foliage and graceful, arching habit make it a standout in any garden. The bottlebrush-like flower plumes add further visual interest and movement.
- ✓ Adds visual interest and texture to the garden
- ✓ Attracts birds
- ✓ Drought tolerant
- ✓ Deer resistant
- ✓ Provides movement in the landscape
- 🐾 Pet Safe
📅 Maintenance Schedule — Plant Care Comparison
Jupiter's Beard
Purple Fountain Grass
🌞 Light Requirements
Jupiter's Beard
Full sun (at least 6 hours of direct sunlight daily)
Low light tolerant: ❌ No
Purple Fountain Grass
Full sun (at least 6 hours of direct sunlight per day)
Low light tolerant: ❌ No
💧 Watering Needs
Jupiter's Beard
Water deeply when the top inch of soil feels dry. Avoid overwatering, as this can lead to root rot. Allow the soil to dry out slightly between waterings. Signs of overwatering include yellowing leaves and a soggy soil. Underwatering is indicated by wilting leaves.
Purple Fountain Grass
Water deeply when the top inch of soil feels dry to the touch. Avoid overwatering, which can lead to root rot. Signs of underwatering include drooping or browning leaves. Signs of overwatering include yellowing leaves and soggy soil.
🌡️ Temperature & Humidity
Jupiter's Beard
Temperature: 15-25°C
Humidity: 30-50%
Purple Fountain Grass
Temperature: 18-30°C
Humidity: 20-50%
🤔 Which Plant Is Right For You?
Jupiter's Beard
Centranthus ruberGardeners looking for a low-maintenance, drought-tolerant plant to add vibrant color to their outdoor landscape.
✅ Choose This Plant If...
- You want a drought-tolerant plant for a sunny garden location.
- You want to attract butterflies and bees to your garden.
- You want a low-maintenance perennial that provides long-lasting color.
- You want a plant that thrives in poor soil conditions.
- You want a plant that is deer-resistant.
❌ Skip This Plant If...
- You are looking for an indoor plant.
- You have pets that may ingest the plant.
- You live in an area where it is considered an invasive species.
Purple Fountain Grass
Pennisetum setaceum 'Rubrum'Gardeners looking for a dramatic ornamental grass to add color and texture to their landscape.
✅ Choose This Plant If...
- You want a striking focal point in your garden.
- You need a drought-tolerant plant for a sunny location.
- You desire a plant with beautiful purple foliage and plumes.
- You want to attract birds to your garden.
- You need a deer-resistant plant.
❌ Skip This Plant If...
- You live in a cold climate and don't want to treat it as an annual.
- You don't have a sunny location.
- You are looking for a low-maintenance indoor plant.
🎯 Quick Verdict
⚡ Key Differences Between These Plants
Jupiter's Beard needs full sun (at least 6 hours of direct sunlight daily), while Purple Fountain Grass prefers full sun (at least 6 hours of direct sunlight per day).
Jupiter's Beard has fast growth, while Purple Fountain Grass grows moderate.
💡 Pro Tips For Comparing These Plants
Jupiter's Beard Care Tips
Jupiter's Beard is primarily an outdoor plant and requires full sun and well-draining soil. It is not well-suited for indoor cultivation due to its high light needs and potential for aggressive spreading. Indoor attempts will likely result in a leggy, unhealthy plant.
- Plant in well-draining soil to prevent root rot.
- Provide full sun for optimal flowering.
- Deadhead spent flowers regularly to encourage continued blooming.
- Water deeply but infrequently, allowing the soil to dry out slightly between waterings.
- Apply a balanced fertilizer in spring to promote healthy growth.
Purple Fountain Grass Care Tips
Purple Fountain Grass is primarily an outdoor plant and will struggle indoors due to its high light requirements. It needs full sun and well-draining soil. While it can be grown in containers, it requires regular watering and fertilization. Overwintering indoors is possible in colder climates, but the plant may not thrive.
- Plant in well-draining soil in a sunny location.
- Water deeply but infrequently, allowing the soil to dry out between waterings.
- Fertilize in spring with a balanced slow-release fertilizer.
- Cut back foliage in late fall or early spring.
- Protect from frost in colder climates.
⚠️ Common Problems & Solutions — Plant Care Comparison
Jupiter's Beard
Purple Fountain Grass
❓ Frequently Asked Questions — Comparing These Plants
Jupiter's Beard
What are the light requirements for Jupiter's Beard?
Jupiter’s Beard flourishes in full sun, requiring at least 6-8 hours of direct sunlight daily for optimal growth and abundant flowering. Insufficient sunlight can result in leggy growth, reduced flowering, and weaker stems. While it can tolerate partial shade, the flowering will be significantly reduced.
How do I care for Jupiter's Beard?
Jupiter’s Beard thrives in well-draining soil and prefers full sun for optimal flowering. Water thoroughly when the top inch of soil feels dry, but avoid overwatering, as it is drought-tolerant once established. Fertilize sparingly, using a balanced fertilizer in the spring to encourage blooming. Deadhead spent flowers regularly to promote continuous flowering throughout the summer.
How do I propagate Jupiter's Beard?
Jupiter’s Beard can be easily propagated through several methods: division, stem cuttings, and self-seeding (though not controlled).
Purple Fountain Grass
What are the light requirements for Purple Fountain Grass?
Purple Fountain Grass requires at least 6-8 hours of direct sunlight per day to thrive and develop its characteristic vibrant purple foliage and abundant flower plumes. Insufficient sunlight can lead to leggy growth, faded color, and reduced flowering. When planting, choose a location that receives full sun throughout the day. If growing in containers, rotate the plant regularly to ensure even sun exposure on all sides. In hotter climates, some afternoon shade may be beneficial to prevent scorching, but avoid placing it in deep shade, which will hinder its growth. Supplemental lighting may be necessary if grown indoors during winter months.
How do I care for Purple Fountain Grass?
Purple Fountain Grass thrives in full sun and well-draining soil. Water thoroughly when the top inch of soil feels dry, but avoid overwatering, which can lead to root rot. Fertilize monthly during the growing season (spring and summer) with a balanced fertilizer to promote healthy growth and vibrant blooms. Prune away dead or damaged foliage in late winter or early spring before new growth emerges. In colder climates, treat it as an annual or bring it indoors during the winter. Provide adequate air circulation to prevent fungal diseases. Regularly inspect for pests like aphids or spider mites, and treat accordingly. Avoid planting in overly compacted or poorly draining soil. Mulching around the base can help retain moisture and suppress weeds. Protect from strong winds.
How do I propagate Purple Fountain Grass?
Purple Fountain Grass can be propagated by division. In early spring, carefully dig up the plant and divide the root ball into smaller clumps, ensuring each clump has healthy roots and foliage. Replant the divisions in well-draining soil and water thoroughly. Keep the soil consistently moist until the new plants are established. Division is the most reliable method. Seed propagation is possible but can be inconsistent in producing plants true to the ‘Rubrum’ cultivar. Stem cuttings are not typically used for propagating this grass. Keikis are not applicable as this plant doesn’t produce them. Ensure good air circulation to prevent fungal diseases after dividing.
Last updated: April 30, 2026 — Plant care data reviewed and verified by our editorial team.