Australian Tree Fern vs Crown of Thorns Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Australian Tree Fern
Cyathea cooperi
The Australian Tree Fern (Cyathea cooperi) is a fast-growing tree fern characterized by its elegant, arching fronds and distinctive trunk covered in brown scales. It's primarily an outdoor plant, thriving in humid, subtropical environments. Its large size and specific environmental needs make it challenging to grow indoors long-term. People grow it for its tropical appearance and architectural interest in gardens and landscapes. It can reach impressive heights in its natural habitat. The plant's beauty lies in its delicate-looking but resilient fronds.
Crown of Thorns
Euphorbia milii
Euphorbia milii, commonly known as Crown of Thorns, is a succulent shrub characterized by its thorny stems and vibrant bracts surrounding small, inconspicuous flowers. Native to Madagascar, it is a popular ornamental plant grown for its drought tolerance and long-lasting blooms. It typically grows as a sprawling shrub, reaching up to 1-2 meters in height. While it can be grown indoors, it thrives best with ample sunlight, often making it more suitable as an outdoor plant in warmer climates. People grow it for its unique appearance and relatively easy care.
Quick Plant Comparison
| Feature | Australian Tree Fern | Crown of Thorns |
|---|---|---|
| Light | Bright, indirect light to partial shade. Avoid direct sunlight, especially during the hottest part of the day. | Requires at least 4-6 hours of direct sunlight daily. Insufficient light will result in leggy growth and reduced flowering. |
| Watering | Every 2-4 days, depending on environmental conditions and pot size. | Every 2-3 weeks, depending on environmental conditions and pot size. |
| Humidity | 60-80% | 30-50% |
| Temperature | 18-24°C | 18-27°C |
| Care Level | Expert | Moderate |
| Growth Rate | Fast | Slow |
| Max Height | Indoors: 1-2 meters (difficult to maintain this size long-term) | 0.3-0.6 meters (indoors) |
| Pet Safety | ✅ Safe | ❌ Toxic To Pets |
| Soil | Well-draining, slightly acidic soil rich in organic matter. A mix of peat moss, perlite, and tree fern fiber is ideal. | Well-draining succulent or cactus mix |
| Beginner Friendly | ❌ No | With Caution |
| Weekly Maintenance | 30 minutes weekly | 10 minutes weekly |
🔬 Botanical Information — Comparing These Plants
Australian Tree Fern
| Scientific Name | Cyathea cooperi |
|---|---|
| Family | Cyatheaceae |
| Native To | Eastern Australia (New South Wales and Queensland) |
| Also Known As | Australian Tree Fern, Cooper's Cyathea, Lacy Tree Fern |
| Leaves | Large, lacy, bright green fronds that can reach up to 4 meters in length. The fronds are divided into numerous leaflets, giving them a delicate and feathery appearance. |
| Flowers | Does not flower indoors. Tree ferns reproduce via spores, not flowers. |
Crown of Thorns
| Scientific Name | Euphorbia milii |
|---|---|
| Family | Euphorbiaceae |
| Native To | Madagascar |
| Also Known As | Crown of Thorns, Christ Plant, Christ Thorn |
| Leaves | The leaves are small, oval-shaped, and typically bright green. They are deciduous, meaning they may drop off during periods of stress or dormancy, especially in winter. |
| Flowers | It can flower indoors, but flowering is more prolific with ample sunlight. The true flowers are small and inconspicuous, surrounded by colorful bracts that can be red, pink, yellow, or white. |
📏 Size & Growth — Plant Comparison
Australian Tree Fern
Crown of Thorns
🌱 Propagation — Comparing Plant Growth
Australian Tree Fern
Methods: Spores, Division (of pups that grow at the base of the trunk)
Difficulty: Difficult
Tips: Spore propagation is very slow and requires sterile conditions. Division is more practical but requires careful handling to avoid damaging the parent plant.
Crown of Thorns
Methods: Stem cuttings
Difficulty: Easy
Tips: Allow the cut end to callus over for a few days before planting in well-draining soil. Use rooting hormone for better success.
✨ Benefits & Features — Comparing Plant Value
Australian Tree Fern
The Australian Tree Fern's fast growth rate and large size distinguish it from other ferns. Its trunk, covered in brown scales, adds a unique texture and visual appeal. It's also relatively adaptable to different soil types.
- ✓ Creates a lush, tropical atmosphere
- ✓ Adds architectural interest to gardens
- ✓ Provides a sense of tranquility
- ✓ Can improve indoor air quality slightly by increasing humidity
- ✓ Offers a connection to nature
- 🐾 Pet Safe
Crown of Thorns
The Crown of Thorns is unique due to its thorny stems and the colorful bracts that surround its small flowers. Unlike many flowering plants, the bracts provide color for extended periods, making it a long-lasting ornamental plant.
- ✓ Drought tolerance makes it easy to care for
- ✓ Long-lasting blooms add color to your space
- ✓ Unique appearance provides visual interest
- ✓ Can tolerate neglect, making it suitable for busy individuals
- ✓ Adds a touch of history and symbolism to your plant collection
- ⚠️ Toxic to pets
📅 Maintenance Schedule — Plant Care Comparison
Australian Tree Fern
Crown of Thorns
🌞 Light Requirements
Australian Tree Fern
Bright, indirect light to partial shade. Avoid direct sunlight, especially during the hottest part of the day.
Low light tolerant: ❌ No
Crown of Thorns
Requires at least 4-6 hours of direct sunlight daily. Insufficient light will result in leggy growth and reduced flowering.
Low light tolerant: ❌ No
💧 Watering Needs
Australian Tree Fern
Water frequently to keep the soil consistently moist but not waterlogged. Allow the top inch of soil to slightly dry out before watering again. Overwatering can lead to root rot, while underwatering will cause the fronds to dry and brown. Ensure good drainage.
Crown of Thorns
Allow the soil to dry out completely between waterings. Overwatering can lead to root rot. Water thoroughly when the soil is dry to the touch. Signs of overwatering include yellowing leaves and stem rot. Underwatering will cause leaf drop and shriveling.
🌡️ Temperature & Humidity
Australian Tree Fern
Temperature: 18-24°C
Humidity: 60-80%
Crown of Thorns
Temperature: 18-27°C
Humidity: 30-50%
🤔 Which Plant Is Right For You?
Australian Tree Fern
Cyathea cooperiExperienced plant enthusiasts who can provide the high humidity and bright, indirect light required for this fern to thrive.
✅ Choose This Plant If...
- You want a dramatic, tropical statement plant for a large, bright space.
- You can provide consistently high humidity.
- You are experienced with fern care.
- You live in a mild climate where it can be grown outdoors year-round.
- You have a greenhouse or conservatory.
❌ Skip This Plant If...
- You have limited space.
- You cannot provide high humidity.
- You are a beginner plant owner.
Crown of Thorns
Euphorbia miliiExperienced plant owners who can provide bright light and are aware of the plant's toxicity.
✅ Choose This Plant If...
- You want a drought-tolerant plant that flowers for a long period.
- You have a sunny location where the plant can thrive.
- You are experienced with caring for succulents and understand their watering needs.
- You are looking for a unique and interesting plant with a historical connection.
- You can keep the plant away from pets and children due to its toxicity.
❌ Skip This Plant If...
- You have pets or small children who might ingest the plant.
- You cannot provide adequate sunlight.
- You tend to overwater plants.
- You are looking for a low-maintenance plant that thrives in low-light conditions.
🎯 Quick Verdict
⚡ Key Differences Between These Plants
Australian Tree Fern is rated Expert care level, while Crown of Thorns is Moderate.
Australian Tree Fern has fast growth, while Crown of Thorns grows slow.
💡 Pro Tips For Comparing These Plants
Australian Tree Fern Care Tips
Australian Tree Ferns are challenging to grow indoors due to their high humidity and light requirements. They need consistent moisture and are prone to drying out in typical indoor environments. Maintaining adequate humidity is crucial for their survival. They are best suited for outdoor environments or greenhouses.
- Mist the fronds regularly to increase humidity.
- Use rainwater or distilled water to avoid mineral buildup on the fronds.
- Provide good air circulation to prevent fungal diseases.
- Protect from strong winds, which can damage the fronds.
- Fertilize regularly during the growing season with a balanced liquid fertilizer.
Crown of Thorns Care Tips
Crown of Thorns requires bright sunlight and well-draining soil. Overwatering is a common issue. It can be grown indoors with sufficient light, but may not flower as profusely as when grown outdoors. Toxicity to pets is a significant concern.
- Provide at least 4-6 hours of direct sunlight daily for optimal growth and flowering.
- Allow the soil to dry out completely between waterings to prevent root rot.
- Use a well-draining succulent or cactus mix to ensure proper drainage.
- Fertilize sparingly during the growing season with a balanced liquid fertilizer.
- Wear gloves when pruning or handling the plant to avoid skin irritation from the sap.
⚠️ Common Problems & Solutions — Plant Care Comparison
Australian Tree Fern
Crown of Thorns
❓ Frequently Asked Questions — Comparing These Plants
Australian Tree Fern
What are the light requirements for Australian Tree Fern?
Australian Tree Ferns require bright, indirect light to thrive. Direct sunlight can scorch their delicate fronds, causing them to turn brown and crispy. An east-facing window is often ideal, providing gentle morning light. A north-facing window can also work, especially if supplemented with artificial light. If you place your fern near a south or west-facing window, use a sheer curtain to filter the light.
How do I care for Australian Tree Fern?
The Australian Tree Fern thrives in consistently moist conditions and high humidity. Water thoroughly when the top inch of the soil feels slightly dry. Avoid letting the soil dry out completely, as this can lead to browning fronds. Provide bright, indirect light; direct sunlight can scorch the fronds. Maintain humidity levels above 60% by misting regularly, using a humidifier, or placing the pot on a pebble tray filled with water.
How do I propagate Australian Tree Fern?
Australian Tree Ferns can be propagated by division or spores, though spore propagation is more challenging. For division, carefully separate the trunk into sections, ensuring each section has roots. Plant each section in its own pot with well-draining soil. Keep the soil consistently moist and provide high humidity.
Crown of Thorns
What are the light requirements for Crown of Thorns?
Crown of Thorns requires bright, direct sunlight to thrive. Ideally, place it in a south-facing window where it can receive at least 4-6 hours of sunlight per day. Insufficient light can lead to leggy growth, reduced flowering, and a loss of vibrancy in the bracts. If you don’t have a sufficiently sunny window, consider supplementing with a grow light. Rotate the plant regularly to ensure even light exposure on all sides. During the summer months, you can move your Crown of Thorns outdoors to a sunny location, but be sure to acclimate it gradually to avoid sunburn. The plant’s ability to flower profusely depends on adequate light.
How do I care for Crown of Thorns?
Crown of Thorns thrives on neglect, making it an easy-care succulent. Plant it in well-draining soil, such as a cactus mix, to prevent root rot. Provide it with bright, direct sunlight for at least 4-6 hours daily. Water sparingly, allowing the soil to dry completely between waterings. Reduce watering frequency during the dormant winter months. Fertilize lightly during the growing season (spring and summer) with a balanced liquid fertilizer diluted to half strength. Maintain a room temperature between 65-75°F (18-24°C). Avoid overwatering, as this is the most common cause of problems. Repot every 2-3 years, or when the plant becomes root-bound. Prune to maintain shape and remove dead or damaged stems. Be cautious of the milky sap, which can be irritating to the skin and eyes.
How do I propagate Crown of Thorns?
Crown of Thorns can be propagated through stem cuttings. Allow the cut end to callous over for several days before planting in well-draining soil. Keep the soil slightly moist until roots develop. Leaf cuttings are not generally successful. Offsets, or small plantlets that grow at the base of the plant, can be carefully separated and potted individually. Wear gloves to protect your skin from the irritating sap. Rooting hormone can improve the success rate of stem cuttings. Provide bright, indirect light during the rooting process. Avoid overwatering, as this can lead to rot. Propagation is best done during the growing season (spring and summer).
Last updated: April 20, 2026 — Plant care data reviewed and verified by our editorial team.