Old Man's Beard vs Princess Tree Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Old Man's Beard
Usnea spp.
Old Man's Beard is a lichen, not a plant. It's a symbiotic relationship between a fungus and an alga or cyanobacterium. It appears as stringy, hair-like strands hanging from trees and shrubs. Its color ranges from pale green to grayish-green. It thrives in humid environments with clean air. People collect it for its purported medicinal properties and decorative uses. It is primarily an outdoor organism and cannot be successfully grown indoors.
Princess Tree
Paulownia tomentosa
Paulownia tomentosa, the Princess Tree, is a deciduous tree known for its rapid growth and large, heart-shaped leaves. It can reach heights of 30-60 feet. In spring, it produces fragrant, pale purple flowers in panicles before the leaves emerge. These are followed by persistent seed capsules. While admired for its ornamental value, it's considered invasive in many regions due to its prolific seed production and ability to resprout from roots. It is primarily an outdoor tree and not suitable for indoor cultivation.
Quick Plant Comparison
| Feature | Old Man's Beard | Princess Tree |
|---|---|---|
| Light | Bright, indirect light outdoors. Full sun can scorch it in dry conditions. | Full sun |
| Watering | Dependent on environmental humidity; mist when dry | Once or twice a week during the growing season, less frequently during dormancy. |
| Humidity | 60-90% | 30-50% |
| Temperature | 5-25°C | 15-27°C |
| Care Level | Expert | Expert |
| Growth Rate | Slow | Fast |
| Max Height | Variable, up to several feet long depending on the species and environment. | Not applicable - unsuitable for indoor growing. Outdoors: 9-18 meters |
| Pet Safety | ✅ Safe | ❌ Toxic To Pets |
| Soil | Does not grow in soil. Attaches to tree bark or other surfaces. | Well-draining soil, adaptable to various soil types including clay, loam, and sand. |
| Beginner Friendly | ❌ No | ❌ No |
| Weekly Maintenance | 5 minutes weekly (for misting if needed). | 1-2 hours per month, primarily for pruning and managing spread. |
🔬 Botanical Information — Comparing These Plants
Old Man's Beard
| Scientific Name | Usnea spp. |
|---|---|
| Family | Parmeliaceae |
| Native To | Worldwide, various species have different distributions |
| Also Known As | Old Man's Beard, Tree Moss, Beard Lichen |
| Leaves | Does not have leaves. Consists of thread-like or strap-shaped structures that are pale green to grayish-green in color. |
| Flowers | Does not flower. |
Princess Tree
| Scientific Name | Paulownia tomentosa |
|---|---|
| Family | Paulowniaceae |
| Native To | Central and Western China |
| Also Known As | Princess Tree, Empress Tree, Foxglove Tree |
| Leaves | The leaves are large, heart-shaped (cordate), and can reach up to 12 inches in length. They are typically a medium green color and have a slightly fuzzy texture when young. |
| Flowers | It rarely, if ever, flowers indoors. Outdoors, it produces large panicles of fragrant, pale purple flowers in spring before the leaves emerge. |
📏 Size & Growth — Plant Comparison
Old Man's Beard
Princess Tree
🌱 Propagation — Comparing Plant Growth
Old Man's Beard
Methods: Fragmentation (pieces breaking off and attaching to new surfaces).
Difficulty: Moderate
Tips: Ensure high humidity and a suitable substrate (tree bark). Success is not guaranteed.
Princess Tree
Methods: Seeds, root cuttings, stem cuttings
Difficulty: Moderate
Tips: For seeds, cold stratify for several weeks before sowing. Root cuttings should be taken in late winter. Stem cuttings can be taken in summer.
✨ Benefits & Features — Comparing Plant Value
Old Man's Beard
It is a lichen, not a plant, representing a symbiotic relationship between a fungus and an alga. Its presence indicates good air quality, making it a valuable environmental indicator.
- ✓ Air quality indication
- ✓ Aesthetic appeal in natural settings
- ✓ Potential medicinal properties
- ✓ Educational value
- ✓ Supports biodiversity
- 🐾 Pet Safe
Princess Tree
Its rapid growth rate and large leaves distinguish it from many other trees. The fragrant spring flowers are also a notable feature. However, its invasive nature is a significant consideration.
- ✓ Provides shade in large outdoor spaces.
- ✓ Offers fragrant spring flowers.
- ✓ Attracts pollinators.
- ✓ Provides habitat for wildlife.
- ✓ Can be used for erosion control on slopes.
- ⚠️ Toxic to pets
📅 Maintenance Schedule — Plant Care Comparison
Old Man's Beard
Princess Tree
🌞 Light Requirements
Old Man's Beard
Bright, indirect light outdoors. Full sun can scorch it in dry conditions.
Low light tolerant: ❌ No
Princess Tree
Full sun
Low light tolerant: ❌ No
💧 Watering Needs
Old Man's Beard
Requires high humidity and moisture. In dry climates, misting may be necessary, but it primarily obtains moisture from the air.
Princess Tree
Water deeply when the topsoil feels dry to the touch, especially during the growing season. Avoid overwatering, which can lead to root rot. Reduce watering in the dormant season. Signs of underwatering include wilting leaves; overwatering includes yellowing leaves and soggy soil.
🌡️ Temperature & Humidity
Old Man's Beard
Temperature: 5-25°C
Humidity: 60-90%
Princess Tree
Temperature: 15-27°C
Humidity: 30-50%
🤔 Which Plant Is Right For You?
Old Man's Beard
Usnea spp.Outdoor environments with high humidity and clean air.
✅ Choose This Plant If...
- You live in a naturally humid environment with clean air.
- You want to study lichens and their role in the ecosystem.
- You are interested in traditional medicine and the potential uses of Usnea.
- You have a shaded outdoor area where you can provide high humidity.
- You want a natural air quality indicator.
❌ Skip This Plant If...
- You live in a dry climate.
- You have poor air quality.
- You want an easy-to-care-for houseplant.
Princess Tree
Paulownia tomentosaLandowners with large properties in non-invasive regions who appreciate fast-growing shade trees with showy spring flowers.
✅ Choose This Plant If...
- You have a large outdoor space and want a fast-growing shade tree.
- You appreciate fragrant spring flowers.
- You are prepared to manage its potentially invasive nature.
- You want a tree that can tolerate a variety of soil conditions.
- You are looking for a tree that provides habitat for wildlife.
❌ Skip This Plant If...
- You have a small garden or limited space.
- You live in a region where it is considered invasive.
- You are not prepared to manage its rapid growth and spread.
🎯 Quick Verdict
⚡ Key Differences Between These Plants
Old Man's Beard has slow growth, while Princess Tree grows fast.
💡 Pro Tips For Comparing These Plants
Old Man's Beard Care Tips
Old Man's Beard is an outdoor lichen that is extremely difficult to cultivate indoors. It requires very high humidity, clean air, and specific lighting conditions. It is not a suitable houseplant and will likely die indoors.
- Provide high humidity through regular misting or a humidifier.
- Ensure good air circulation to prevent fungal growth.
- Protect from direct sunlight, especially during the hottest part of the day.
- Monitor for signs of drying out and adjust humidity accordingly.
- Avoid using tap water for misting, as it can contain minerals that harm the lichen.
Princess Tree Care Tips
Paulownia tomentosa is an outdoor tree that requires full sun and well-draining soil. It is not suitable for indoor cultivation due to its size and light requirements. It is considered invasive in many areas, requiring careful management to prevent its spread.
- Monitor for invasive spread and remove seedlings promptly.
- Prune regularly to maintain shape and remove dead or damaged branches.
- Water deeply during dry periods, especially when young.
- Fertilize in early spring with a balanced fertilizer.
- Protect young trees from strong winds.
⚠️ Common Problems & Solutions — Plant Care Comparison
Old Man's Beard
Princess Tree
❓ Frequently Asked Questions — Comparing These Plants
Old Man's Beard
What are the light requirements for Old Man's Beard?
Old Man’s Beard thrives in bright, indirect light. Direct sunlight can scorch its delicate foliage, causing it to dry out and turn brown. The ideal location is near an east- or west-facing window where it receives filtered sunlight. If you’re using artificial light, provide it with several hours of fluorescent or LED grow lights daily.
How do I care for Old Man's Beard?
Caring for Old Man’s Beard is relatively simple, but understanding its needs is crucial for its health and longevity. Place it in a location with bright, indirect light. Avoid direct sunlight, which can scorch the delicate foliage. Water by misting the plant thoroughly 2-3 times a week, or soaking it in water for 15-30 minutes every 1-2 weeks. After soaking, gently shake off excess water to prevent rot.
How do I propagate Old Man's Beard?
Old Man’s Beard is primarily propagated through pups, or offsets, that grow from the main plant. Once a pup reaches about one-third the size of the mother plant, it can be carefully separated. Gently pull or cut the pup from the main strand, ensuring you don’t damage either plant.
Princess Tree
What are the light requirements for Princess Tree?
Princess Tree thrives in bright, indirect light. Insufficient light can lead to leggy growth and reduced leaf size. Place your Princess Tree near a sunny window, ideally facing east or west. If you only have a south-facing window, filter the light with a sheer curtain to prevent scorching. Rotate the plant regularly to ensure even light exposure on all sides. If natural light is limited, consider supplementing with artificial grow lights to provide the necessary light intensity. Pale leaves or slow growth can indicate insufficient light.
How do I care for Princess Tree?
To successfully grow Princess Tree indoors, provide it with bright, indirect light; direct sunlight can scorch the leaves. Water thoroughly when the top inch of soil feels dry, ensuring good drainage to prevent root rot. Maintain moderate humidity levels, especially during the winter months when indoor air tends to be drier. Fertilize regularly during the growing season (spring and summer) with a balanced liquid fertilizer diluted to half strength. Repot the plant every 1-2 years, or when it becomes root-bound, using a well-draining potting mix. Prune as needed to maintain shape and remove any dead or damaged leaves. Monitor for pests such as spider mites and aphids, and treat promptly with insecticidal soap or neem oil. Maintain stable temperatures, avoiding drastic fluctuations.
How do I propagate Princess Tree?
Princess Tree can be propagated through stem cuttings and air layering.
Last updated: April 26, 2026 — Plant care data reviewed and verified by our editorial team.