Alyssum vs Princess Tree Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Alyssum
Lobularia maritima
Sweet Alyssum (Lobularia maritima) is a low-growing, spreading annual or short-lived perennial, typically grown as an annual. It reaches a height of 6-12 inches and spreads 12-18 inches wide. It features masses of tiny, fragrant flowers, usually white but also available in pink, purple, and yellow shades. Primarily an outdoor plant, it's popular for borders, rock gardens, and containers due to its profuse blooms and sweet honey-like scent. While it can be attempted indoors, maintaining sufficient light and cool temperatures is challenging.
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 | Alyssum | Princess Tree |
|---|---|---|
| Light | Full sun to partial shade outdoors. Indoors, requires very bright, direct light for at least 6 hours daily. | Full sun |
| Watering | Every 2-3 days outdoors in warm weather; every 5-7 days indoors, depending on light and temperature. | Once or twice a week during the growing season, less frequently during dormancy. |
| Humidity | 30-50% | 30-50% |
| Temperature | 15-24°C | 15-27°C |
| Care Level | Expert | Expert |
| Growth Rate | Moderate | Fast |
| Max Height | 6-12 inches (indoors, typically smaller) | Not applicable - unsuitable for indoor growing. Outdoors: 9-18 meters |
| Pet Safety | ❌ Toxic To Pets | ❌ Toxic To Pets |
| Soil | Well-draining potting mix. A mix of potting soil, perlite, and vermiculite is suitable. | Well-draining soil, adaptable to various soil types including clay, loam, and sand. |
| Beginner Friendly | ❌ No | ❌ No |
| Weekly Maintenance | 15 minutes weekly | 1-2 hours per month, primarily for pruning and managing spread. |
🔬 Botanical Information — Comparing These Plants
Alyssum
| Scientific Name | Lobularia maritima |
|---|---|
| Family | Brassicaceae |
| Native To | Mediterranean region, Canary Islands |
| Also Known As | Sweet Alyssum, Sweet Alison |
| Leaves | Small, lance-shaped, and grayish-green. The leaves are typically less than an inch long and have a slightly hairy texture. |
| Flowers | Flowers profusely outdoors. Indoors, flowering is possible with sufficient light. The flowers are tiny, four-petaled, and typically white, but also available in pink, purple, and yellow shades. They are clustered together in masses, creating a showy display. |
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
Alyssum
Princess Tree
🌱 Propagation — Comparing Plant Growth
Alyssum
Methods: Seed, Stem cuttings
Difficulty: Easy
Tips: For seeds, sow indoors 6-8 weeks before the last frost or directly outdoors after the last frost. For stem cuttings, take 2-3 inch cuttings and root them in water or moist potting mix.
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
Alyssum
Sweet Alyssum is known for its profuse blooms and sweet, honey-like fragrance. Its low-growing, spreading habit makes it ideal for borders and rock gardens. It is also attractive to beneficial insects.
- ✓ Attracts pollinators to the garden.
- ✓ Provides a sweet, honey-like fragrance.
- ✓ Adds a splash of color to borders and containers.
- ✓ Can be used as a ground cover.
- ✓ Provides a calming aesthetic.
- ⚠️ Toxic to pets
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
Alyssum
Princess Tree
🌞 Light Requirements
Alyssum
Full sun to partial shade outdoors. Indoors, requires very bright, direct light for at least 6 hours daily.
Low light tolerant: ❌ No
Princess Tree
Full sun
Low light tolerant: ❌ No
💧 Watering Needs
Alyssum
Water thoroughly when the top inch of soil feels dry. Avoid overwatering, which can lead to root rot. Allow the soil to drain completely after watering. Indoors, monitor closely as soil dries out faster in bright light.
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
Alyssum
Temperature: 15-24°C
Humidity: 30-50%
Princess Tree
Temperature: 15-27°C
Humidity: 30-50%
🤔 Which Plant Is Right For You?
Alyssum
Lobularia maritimaExperienced gardeners who want a fragrant, flowering plant for outdoor borders, rock gardens, or containers.
✅ Choose This Plant If...
- You want a plant with a sweet, honey-like fragrance.
- You need a low-growing plant for borders or rock gardens.
- You want to attract pollinators to your garden.
- You enjoy plants that bloom profusely.
- You are an experienced gardener willing to provide the high light levels needed indoors.
❌ Skip This Plant If...
- You have pets that might ingest the plant.
- You cannot provide very bright, direct light.
- You prefer low-maintenance indoor plants.
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
Alyssum has moderate growth, while Princess Tree grows fast.
💡 Pro Tips For Comparing These Plants
Alyssum Care Tips
Sweet Alyssum is primarily an outdoor plant. Indoor cultivation is challenging due to its high light requirements and preference for cooler temperatures. It needs very bright, direct light and well-draining soil. Overwatering and lack of sufficient light are common problems indoors.
- Provide at least 6 hours of direct sunlight daily for indoor plants.
- Use well-draining soil to prevent root rot.
- Deadhead spent flowers regularly to encourage continuous blooming.
- Fertilize every 2-4 weeks during the growing season.
- Monitor for pests like aphids and treat promptly.
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
Alyssum
Princess Tree
❓ Frequently Asked Questions — Comparing These Plants
Alyssum
What are the light requirements for Alyssum?
Alyssum prefers full sun, requiring at least 6 hours of direct sunlight each day to thrive and produce abundant blooms. However, in hotter climates, it benefits from some afternoon shade to prevent scorching of the delicate flowers and foliage. Insufficient light can lead to leggy growth, reduced flowering, and pale foliage.
How do I care for Alyssum?
Alyssum thrives in full sun to partial shade. Aim for at least 6 hours of sunlight daily for optimal blooming. Plant in well-draining soil with a slightly acidic to neutral pH (6.0-7.0). Water regularly, allowing the soil to dry slightly between waterings. Avoid overwatering, as this can lead to root rot. Fertilize every 2-3 weeks during the growing season with a balanced liquid fertilizer, focusing on formulas that promote blooming.
How do I propagate Alyssum?
Alyssum can be propagated through seeds, stem cuttings, and division. For stem cuttings, take 4-6 inch cuttings from healthy stems, remove the lower leaves, and dip the cut end in rooting hormone. Plant the cuttings in moist potting mix and keep them in a humid environment until rooted.
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: May 2, 2026 — Plant care data reviewed and verified by our editorial team.