Chocolate Cosmos vs Pellaea Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Chocolate Cosmos
Cosmos atrosanguineus
Chocolate Cosmos is a tuberous perennial plant prized for its dark, velvety, chocolate-scented flowers. It typically grows to a height of 40-60 cm. The flowers are usually a deep maroon to chocolate brown color and bloom from summer to frost. While it can be grown in containers, it is primarily an outdoor plant that requires specific conditions to thrive. People grow it for its unique flower color, fragrance, and ornamental value in gardens.
Pellaea
Pellaea rotundifolia
Pellaea rotundifolia, commonly known as the Button Fern, is a small, evergreen fern characterized by its round, button-like leaflets. It features dark green, leathery foliage that grows along wiry, arching fronds. Unlike many ferns that prefer high humidity, the Button Fern is relatively drought-tolerant, making it a popular choice for indoor environments. It typically grows to a height and spread of about 12-18 inches. Its compact size and unique leaf shape make it a charming addition to any plant collection. It's often grown in hanging baskets or small pots.
Quick Plant Comparison
| Feature | Chocolate Cosmos | Pellaea |
|---|---|---|
| Light | Full sun to partial shade. Requires at least 6 hours of direct sunlight for optimal flowering. | Bright, indirect light. Avoid direct sunlight, which can scorch the fronds. |
| Watering | Every 3-7 days during the growing season, depending on weather and soil drainage. | Every 1-2 weeks, depending on environmental conditions. |
| Humidity | 40-60% | 40-60% |
| Temperature | 18-24°C | 18-24°C |
| Care Level | Expert | Moderate |
| Growth Rate | Moderate | Slow |
| Max Height | 40-60 cm | 30-45 cm |
| Pet Safety | ❌ Toxic To Pets | ✅ Safe |
| Soil | Well-draining soil, such as a mix of potting soil, perlite, and sand. | Well-draining potting mix, such as a mix of peat moss, perlite, and vermiculite. |
| Beginner Friendly | ❌ No | With Caution |
| Weekly Maintenance | 15 minutes weekly | 5-10 minutes weekly |
🔬 Botanical Information — Comparing These Plants
Chocolate Cosmos
| Scientific Name | Cosmos atrosanguineus |
|---|---|
| Family | Asteraceae |
| Native To | Mexico (endemic to a small area in Mexico; now extinct in the wild) |
| Also Known As | Chocolate Cosmos |
| Leaves | The leaves are pinnately divided, resembling ferns, and are a medium green color. They are finely textured and provide a delicate backdrop to the dark flowers. |
| Flowers | While it may flower indoors under ideal conditions (very bright light), it is more commonly and reliably flowered outdoors. The flowers are typically a deep maroon to chocolate brown color and have a velvety texture. They are approximately 3-5 cm in diameter and have a distinct chocolate scent. |
Pellaea
| Scientific Name | Pellaea rotundifolia |
|---|---|
| Family | Pteridaceae |
| Native To | New Zealand |
| Also Known As | Button Fern, Round-leaf Fern |
| Leaves | The leaves are composed of small, round, dark green leaflets that resemble buttons. The leaflets are leathery in texture and arranged along wiry, dark brown or black stems. Each frond can reach up to 12 inches in length. |
| Flowers | Button Ferns do not produce flowers indoors. They reproduce via spores, which are located on the underside of the fronds. |
📏 Size & Growth — Plant Comparison
Chocolate Cosmos
Pellaea
🌱 Propagation — Comparing Plant Growth
Chocolate Cosmos
Methods: Division, Tubers, Seed (though seed propagation can be challenging and may not produce true-to-type offspring)
Difficulty: Moderate
Tips: Divide tubers in early spring before new growth begins. Plant tubers in well-draining soil and keep moist until established. Seeds can be sown indoors 6-8 weeks before the last frost.
Pellaea
Methods: Spores, Division
Difficulty: Moderate
Tips: Division is best done in spring. Carefully separate the rhizomes and plant them in individual pots. Spores can be collected and sown on a moist surface, but this method is more challenging.
✨ Benefits & Features — Comparing Plant Value
Chocolate Cosmos
The Chocolate Cosmos is unique for its dark, velvety flowers and distinct chocolate scent. It is also notable for being extinct in the wild, with all cultivated plants being clones of a single specimen.
- ✓ Aesthetic appeal with unique dark flowers.
- ✓ Pleasant chocolate fragrance enhances outdoor spaces.
- ✓ Attracts pollinators like bees and butterflies.
- ✓ Provides cut flowers for arrangements.
- ✓ Adds visual interest to garden borders and containers.
- ⚠️ Toxic to pets
Pellaea
The Button Fern is unique due to its small, round leaflets, which give it a distinctive appearance compared to other ferns. Its drought tolerance also sets it apart, making it a more forgiving option for those who tend to underwater.
- ✓ Adds a touch of greenery to indoor spaces.
- ✓ Relatively low-maintenance compared to other ferns.
- ✓ Unique foliage provides visual interest.
- ✓ Can help improve indoor air quality by removing some toxins.
- ✓ Creates a calming and relaxing atmosphere.
- 🐾 Pet Safe
📅 Maintenance Schedule — Plant Care Comparison
Chocolate Cosmos
Pellaea
🌞 Light Requirements
Chocolate Cosmos
Full sun to partial shade. Requires at least 6 hours of direct sunlight for optimal flowering.
Low light tolerant: ❌ No
Pellaea
Bright, indirect light. Avoid direct sunlight, which can scorch the fronds.
Low light tolerant: ❌ No
💧 Watering Needs
Chocolate Cosmos
Water regularly during the growing season, allowing the top inch of soil to dry out between waterings. Avoid overwatering, which can lead to tuber rot. Reduce watering in the fall as the plant prepares for dormancy. Signs of overwatering include yellowing leaves and a mushy stem base. Underwatering results in wilting and dry, crispy leaves.
Pellaea
Water thoroughly when the top inch of soil feels dry to the touch. Avoid overwatering, as this can lead to root rot. Allow excess water to drain away. Signs of overwatering include yellowing or browning leaves and a soggy soil. Underwatering can cause the fronds to become dry and brittle.
🌡️ Temperature & Humidity
Chocolate Cosmos
Temperature: 18-24°C
Humidity: 40-60%
Pellaea
Temperature: 18-24°C
Humidity: 40-60%
🤔 Which Plant Is Right For You?
Chocolate Cosmos
Cosmos atrosanguineusExperienced gardeners who want a unique and fragrant addition to their outdoor garden.
✅ Choose This Plant If...
- You love the unique chocolate scent of the flowers.
- You want a plant with unusual dark-colored blooms.
- You have a sunny garden or patio.
- You enjoy a challenge and are willing to provide the specific care this plant needs.
- You want to attract pollinators to your garden.
❌ Skip This Plant If...
- You have pets that might ingest the plant.
- You don't have a sunny location.
- You are a beginner gardener looking for an easy-care plant.
Pellaea
Pellaea rotundifoliaSomeone who wants a low-maintenance fern with a unique appearance.
✅ Choose This Plant If...
- You want a fern that's relatively easy to care for.
- You appreciate unique foliage textures and shapes.
- You need a plant that can tolerate slightly drier conditions than other ferns.
- You have a bright, indirect light location.
- You want a compact plant that fits well in small spaces.
❌ Skip This Plant If...
- You tend to overwater your plants.
- You have a very dark home with little natural light.
- You are looking for a fast-growing plant.
🎯 Quick Verdict
⚡ Key Differences Between These Plants
Chocolate Cosmos is rated Expert care level, while Pellaea is Moderate.
Chocolate Cosmos has moderate growth, while Pellaea grows slow.
💡 Pro Tips For Comparing These Plants
Chocolate Cosmos Care Tips
Chocolate Cosmos is primarily an outdoor plant and requires specific conditions to thrive indoors. It needs ample sunlight, well-draining soil, and careful watering to prevent tuber rot. Indoor cultivation is challenging due to the high light requirements and the need for a cool, dry dormancy period in winter.
- Provide at least 6 hours of direct sunlight daily for optimal flowering.
- Ensure well-draining soil to prevent tuber rot.
- Fertilize regularly during the growing season with a balanced liquid fertilizer.
- Deadhead spent flowers to encourage more blooms.
- Protect from frost in colder climates by lifting and storing tubers indoors.
Pellaea Care Tips
Button Ferns are relatively easy to care for, but they require bright, indirect light and well-draining soil. Avoid overwatering and provide moderate humidity. They are more drought-tolerant than many other ferns.
- Allow the top inch of soil to dry out before watering.
- Avoid placing the plant in direct sunlight.
- Provide moderate humidity by misting occasionally or using a humidifier.
- Fertilize sparingly during the growing season.
- Repot every 2-3 years to refresh the soil.
⚠️ Common Problems & Solutions — Plant Care Comparison
Chocolate Cosmos
Pellaea
❓ Frequently Asked Questions — Comparing These Plants
Chocolate Cosmos
What are the light requirements for Chocolate Cosmos?
Chocolate Cosmos requires at least six hours of direct sunlight daily to thrive and produce abundant blooms. When grown indoors, place it near a sunny window, preferably south-facing. If natural light is insufficient, supplement with grow lights. Insufficient light can lead to leggy growth and reduced flowering. Rotate the plant regularly to ensure even light exposure on all sides. Plants grown in too much shade will produce fewer blooms and may become susceptible to fungal diseases. Monitor the plant’s foliage; pale or yellowish leaves can indicate insufficient light.
How do I care for Chocolate Cosmos?
Chocolate Cosmos thrives in well-draining soil and prefers full sun to partial shade. Water regularly, allowing the soil to dry slightly between waterings; avoid overwatering to prevent root rot. Fertilize every 2-4 weeks during the growing season with a balanced, water-soluble fertilizer, or one specifically formulated for blooming plants. Deadhead spent flowers to encourage continuous blooming. In colder climates, protect from frost or bring indoors during winter. Chocolate Cosmos benefits from consistent humidity, especially when grown indoors. Ensure good air circulation to prevent fungal diseases. Regularly check for pests and address them promptly. Prune back in late fall to encourage bushier growth the following season.
How do I propagate Chocolate Cosmos?
Chocolate Cosmos can be propagated by division or stem cuttings.
Pellaea
What are the light requirements for Pellaea?
Pellaea ferns thrive in bright, indirect light. They cannot tolerate direct sunlight, which can scorch their delicate fronds. An east-facing window is often ideal, providing gentle morning light. If placing near a south- or west-facing window, use a sheer curtain to filter the light. Too little light can lead to leggy growth and faded color. Rotate the plant regularly to ensure even light exposure on all sides.
How do I care for Pellaea?
Pellaea ferns require bright, indirect light. Avoid direct sunlight, which can scorch the fronds. Water thoroughly when the top inch of soil feels dry, but avoid overwatering, as this can lead to root rot. Maintain high humidity by misting regularly, using a humidifier, or placing the plant on a pebble tray. Use well-draining potting mix suitable for ferns. Fertilize monthly during the growing season (spring and summer) with a diluted balanced fertilizer.
How do I propagate Pellaea?
Pellaea ferns can be propagated by division or spores. For division, carefully remove the plant from its pot and gently separate the rhizomes into smaller clumps, ensuring each clump has healthy roots and fronds. Repot each clump into its own pot with well-draining potting mix. Keep the soil consistently moist and provide high humidity.
Last updated: April 24, 2026 — Plant care data reviewed and verified by our editorial team.