Kentucky Coffeetree vs Purple Fountain Grass Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Kentucky Coffeetree
Gymnocladus dioicus
The Kentucky Coffeetree is a large, deciduous tree known for its bold, coarse texture and unique branching pattern. It typically reaches 60-75 feet in height with a broad, spreading crown. Its leaves are bipinnately compound, among the largest of any tree in North America, giving it a tropical appearance. It is primarily grown as an ornamental tree for its interesting winter silhouette and tolerance of urban conditions. It is not suitable as an indoor plant.
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 | Kentucky Coffeetree | Purple Fountain Grass |
|---|---|---|
| Light | Full sun | Full sun (at least 6 hours of direct sunlight per day) |
| Watering | Once or twice a week during the growing season, less frequently during dormancy. | Every 7-10 days, depending on weather and soil drainage |
| Humidity | 30-50% | 20-50% |
| Temperature | 10-30°C | 18-30°C |
| Care Level | Expert | Expert |
| Growth Rate | Moderate | Moderate |
| Max Height | N/A (Outdoor tree, not suitable for indoor growing) | Outdoor: 0.6-1.5 meters. Indoor (unlikely to thrive): 0.3-0.6 meters |
| Pet Safety | ❌ Toxic To Pets | ✅ Safe |
| Soil | Well-drained soil; adaptable to various soil types including clay, loam, and sand. | Well-draining soil, such as a sandy loam or a potting mix amended with perlite |
| Beginner Friendly | ❌ No | ❌ No |
| Weekly Maintenance | 30 minutes monthly (primarily for pruning and cleanup) | 15 minutes weekly |
🔬 Botanical Information — Comparing These Plants
Kentucky Coffeetree
| Scientific Name | Gymnocladus dioicus |
|---|---|
| Family | Fabaceae |
| Native To | Eastern and Central United States |
| Also Known As | Kentucky Coffeetree, Coffeenut |
| Leaves | The leaves are bipinnately compound, meaning they are divided into multiple leaflets. They can be up to 3 feet long and 2 feet wide, with each leaflet being oval-shaped and 2-4 inches long. The leaves emerge bronze-pink in spring, turn dark green in summer, and yellow in fall. |
| Flowers | The Kentucky Coffeetree produces fragrant, greenish-white flowers in late spring to early summer. However, it is dioecious, meaning that male and female flowers are borne on separate trees. Only female trees produce seed pods. |
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
Kentucky Coffeetree
Purple Fountain Grass
🌱 Propagation — Comparing Plant Growth
Kentucky Coffeetree
Methods: Seed, Root cuttings
Difficulty: Moderate
Tips: Seeds require scarification and stratification before planting. Root cuttings should be taken in late winter or early spring.
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
Kentucky Coffeetree
The Kentucky Coffeetree is distinguished by its large, bipinnately compound leaves, which are among the largest of any tree in North America. Its bold, coarse texture and unique branching pattern, especially visible in winter, make it a striking ornamental tree.
- ✓ Provides shade in the summer
- ✓ Adds visual interest to the landscape, especially in winter
- ✓ Tolerates urban conditions and air pollution
- ✓ Requires minimal maintenance once established
- ✓ Provides habitat for birds and other wildlife
- ⚠️ 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
Kentucky Coffeetree
Purple Fountain Grass
🌞 Light Requirements
Kentucky Coffeetree
Full sun
Low light tolerant: ❌ No
Purple Fountain Grass
Full sun (at least 6 hours of direct sunlight per day)
Low light tolerant: ❌ No
💧 Watering Needs
Kentucky Coffeetree
Water deeply and regularly, especially during the first few years after planting, to establish a strong root system. Once established, it is relatively drought-tolerant. Overwatering can lead to root rot, so ensure the soil drains well. Check soil moisture before watering.
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
Kentucky Coffeetree
Temperature: 10-30°C
Humidity: 30-50%
Purple Fountain Grass
Temperature: 18-30°C
Humidity: 20-50%
🤔 Which Plant Is Right For You?
Kentucky Coffeetree
Gymnocladus dioicusHomeowners with large yards seeking a unique, low-maintenance shade tree.
✅ Choose This Plant If...
- You want a shade tree with a unique branching pattern, especially in winter.
- You need a tree that tolerates urban conditions and air pollution.
- You want a low-maintenance tree once it's established.
- You appreciate the tree's large, tropical-looking leaves.
- You want a tree that provides habitat for wildlife.
❌ Skip This Plant If...
- You have limited space in your yard.
- You have pets or livestock that might ingest toxic plant parts.
- You prefer evergreen trees.
- You dislike the litter from seed pods.
- You live in a climate with extremely cold winters where it may not thrive.
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
Kentucky Coffeetree needs full sun, while Purple Fountain Grass prefers full sun (at least 6 hours of direct sunlight per day).
Kentucky Coffeetree has moderate growth, while Purple Fountain Grass grows moderate.
💡 Pro Tips For Comparing These Plants
Kentucky Coffeetree Care Tips
The Kentucky Coffeetree is an outdoor tree that requires full sun and well-drained soil. It is not suitable for indoor growing. It is relatively low-maintenance once established but requires proper planting and initial care. Toxicity to pets is a major concern.
- Plant in well-drained soil to prevent root rot.
- Water deeply and regularly during the first few years to establish a strong root system.
- Prune in late winter or early spring to remove dead or damaged branches.
- Fertilize in early spring with a balanced fertilizer.
- Monitor for pests and diseases and treat promptly.
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
Kentucky Coffeetree
Purple Fountain Grass
❓ Frequently Asked Questions — Comparing These Plants
Kentucky Coffeetree
What are the light requirements for Kentucky Coffeetree?
Kentucky Coffeetrees thrive in bright, indirect light when grown indoors. Direct sunlight can scorch their leaves, especially when young. An east- or west-facing window provides ideal conditions. If placed near a south-facing window, use a sheer curtain to filter the light.
How do I care for Kentucky Coffeetree?
Kentucky Coffeetrees grown indoors need bright, indirect light. Water thoroughly when the top inch of soil is dry, ensuring good drainage to prevent root rot. Use a well-draining potting mix formulated for trees. Maintain humidity around 40-60%. Fertilize during the growing season (spring and summer) with a balanced liquid fertilizer diluted to half strength every 4-6 weeks.
How do I propagate Kentucky Coffeetree?
Kentucky Coffeetrees can be propagated through stem cuttings or air layering, although stem cuttings can be challenging.
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: May 7, 2026 — Plant care data reviewed and verified by our editorial team.