Physostegia vs Princess Flower Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Physostegia
Physostegia virginiana
Physostegia virginiana, commonly known as Obedient Plant, is a herbaceous perennial native to North America. It features upright, square stems and lance-shaped, toothed leaves. The plant is known for its unique flowers that bloom in late summer and fall, forming dense spikes of tubular, pink, lavender, or white blossoms. The common name comes from the fact that if you gently push a flower to one side, it will often stay in that position. It is primarily an outdoor plant, valued for its late-season blooms and ability to attract pollinators. It can be challenging to grow indoors due to its high light requirements and tendency to spread.
Princess Flower
Tibouchina urvilleana
Tibouchina urvilleana, commonly known as Princess Flower, is a fast-growing evergreen shrub or small tree prized for its vibrant purple flowers. Native to Brazil, it typically grows outdoors in warm climates. It features velvety, dark green leaves and produces profuse blooms throughout the warmer months. While it can be grown in containers, it requires significant sunlight and humidity to thrive, making it challenging to maintain indoors long-term. People grow it for its showy flowers and tropical appearance.
Quick Plant Comparison
| Feature | Physostegia | Princess Flower |
|---|---|---|
| Light | Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal flowering. | Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal flowering. |
| Watering | Every 7-10 days outdoors, less frequently if in partial shade or cooler conditions. | Every 3-7 days, depending on environmental conditions and pot size. |
| Humidity | 30-50% | 50-70% |
| Temperature | 18-27°C | 18-27°C |
| Care Level | Expert | Expert |
| Growth Rate | Fast | Fast |
| Max Height | Indoors: Rarely exceeds 60 cm (2 feet) and is unlikely to thrive. Outdoors: 60-120 cm (2-4 feet) | 1-2 meters (indoors, rarely reaches outdoor size) |
| Pet Safety | ✅ Safe | ❌ Toxic To Pets |
| Soil | Well-drained soil, loamy or sandy soil is best. Amend heavy clay soils with organic matter. | Well-draining, slightly acidic soil mix. A mix of potting soil, peat moss, and perlite is suitable. |
| Beginner Friendly | ❌ No | ❌ No |
| Weekly Maintenance | Outdoors: 15-30 minutes weekly, including watering, weeding, and pruning. Indoors: 30-45 minutes weekly, including watering, fertilizing, and monitoring for pests and diseases. | 30 minutes weekly |
🔬 Botanical Information — Comparing These Plants
Physostegia
| Scientific Name | Physostegia virginiana |
|---|---|
| Family | Lamiaceae |
| Native To | Eastern and Central North America |
| Also Known As | Obedient Plant, False Dragonhead |
| Leaves | Lance-shaped, toothed leaves that are typically 5-15 cm (2-6 inches) long. The leaves are arranged oppositely along the stems and are a medium green color. |
| Flowers | Flowers bloom in late summer and fall, forming dense spikes of tubular, pink, lavender, or white blossoms. Rarely flowers indoors unless provided with intense supplemental lighting. |
Princess Flower
| Scientific Name | Tibouchina urvilleana |
|---|---|
| Family | Melastomataceae |
| Native To | Brazil |
| Also Known As | Princess Flower, Glory Bush, Lasiandra |
| Leaves | Oppositely arranged, ovate to lance-shaped leaves with a velvety texture. The leaves are typically dark green and can grow up to 15 cm long. |
| Flowers | Produces profuse, showy purple flowers with prominent stamens. Flowers are typically 7-10 cm in diameter. Flowering is less likely indoors due to insufficient light. |
📏 Size & Growth — Plant Comparison
Physostegia
Princess Flower
🌱 Propagation — Comparing Plant Growth
Physostegia
Methods: Division, Seed, Stem cuttings
Difficulty: Easy
Tips: Divide rhizomes in spring or fall. Take stem cuttings in late spring or early summer. Sow seeds in spring or fall.
Princess Flower
Methods: Stem cuttings, Seed
Difficulty: Moderate
Tips: Take stem cuttings in spring or summer. Dip the cut end in rooting hormone and plant in moist potting mix. Keep the cuttings in a warm, humid environment until roots develop.
✨ Benefits & Features — Comparing Plant Value
Physostegia
The 'obedient' nature of the flowers, where they stay in place when gently moved, is a unique characteristic. It also blooms later in the season than many other perennials, providing color when other plants are fading.
- ✓ Attracts pollinators to your garden.
- ✓ Provides late-season color.
- ✓ Easy to propagate and share with friends.
- ✓ Adds a unique texture and form to the landscape.
- ✓ Supports local ecosystems by providing food and habitat for wildlife.
- 🐾 Pet Safe
Princess Flower
The velvety texture of the leaves and the vibrant purple color of the flowers make this plant stand out. It's also a fast grower, quickly filling in garden spaces.
- ✓ Provides vibrant color to gardens and patios.
- ✓ Attracts pollinators like bees and butterflies.
- ✓ Can be pruned into a desired shape.
- ✓ Offers a tropical aesthetic.
- ✓ Can be grown in containers on patios or balconies.
- ⚠️ Toxic to pets
📅 Maintenance Schedule — Plant Care Comparison
Physostegia
Princess Flower
🌞 Light Requirements
Physostegia
Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal flowering.
Low light tolerant: ❌ No
Princess Flower
Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal flowering.
Low light tolerant: ❌ No
💧 Watering Needs
Physostegia
Water deeply when the top inch of soil feels dry. Avoid overwatering, which can lead to root rot. Signs of underwatering include wilting leaves and dry soil. Signs of overwatering include yellowing leaves and soggy soil.
Princess Flower
Water thoroughly when the top inch of soil feels dry. Avoid overwatering, which can lead to root rot. Allow excess water to drain away. Signs of underwatering include wilting leaves; signs of overwatering include yellowing leaves and soggy soil.
🌡️ Temperature & Humidity
Physostegia
Temperature: 18-27°C
Humidity: 30-50%
Princess Flower
Temperature: 18-27°C
Humidity: 50-70%
🤔 Which Plant Is Right For You?
Physostegia
Physostegia virginianaGardeners looking for late-season blooms and a plant that attracts pollinators in an outdoor setting.
✅ Choose This Plant If...
- You want a plant that attracts butterflies and hummingbirds to your garden.
- You need a late-season bloomer to extend your garden's color.
- You have a sunny spot in your garden where it can thrive.
- You enjoy the unique 'obedient' characteristic of the flowers.
- You want a plant that is relatively easy to propagate.
❌ Skip This Plant If...
- You have limited sunlight indoors, as it requires full sun to thrive.
- You don't want a plant that spreads aggressively.
- You are looking for a low-maintenance indoor plant.
Princess Flower
Tibouchina urvilleanaExperienced gardeners in warm climates who want a showy flowering shrub for their garden.
✅ Choose This Plant If...
- You live in a warm climate with plenty of sunshine.
- You want a plant with vibrant purple flowers.
- You have experience caring for demanding plants.
- You have a greenhouse or sunroom to provide adequate light and humidity.
- You are willing to provide regular pruning and fertilization.
❌ Skip This Plant If...
- You live in a cold climate with limited sunlight.
- You are a beginner gardener.
- You have pets that may ingest the plant.
- You don't have time for regular pruning and fertilization.
- You don't have a bright, sunny location.
🎯 Quick Verdict
⚡ Key Differences Between These Plants
Both plants have similar basic care requirements but differ in appearance and specific needs. Compare plants carefully to find the best fit for your space.
💡 Pro Tips For Comparing These Plants
Physostegia Care Tips
Physostegia virginiana is primarily an outdoor plant that requires full sun and well-drained soil. It is challenging to grow indoors due to its high light requirements and aggressive spreading habit. Indoor cultivation requires very bright light, careful watering, and frequent repotting to manage its growth.
- Plant in well-drained soil to prevent root rot.
- Provide full sun for optimal flowering.
- Divide plants every 2-3 years to control spread and rejuvenate growth.
- Water deeply but infrequently, allowing the soil to dry out slightly between waterings.
- Deadhead spent flowers to encourage further blooming.
Princess Flower Care Tips
Princess Flower is primarily an outdoor plant that requires full sun and high humidity. Indoor cultivation is challenging due to the difficulty of providing adequate light and humidity. It needs regular watering and fertilization. Expect reduced flowering and potential pest issues indoors.
- Provide at least 6 hours of direct sunlight daily.
- Water thoroughly when the top inch of soil is dry.
- Fertilize regularly during the growing season.
- Prune after flowering to maintain shape.
- Monitor for pests and diseases regularly.
⚠️ Common Problems & Solutions — Plant Care Comparison
Physostegia
Princess Flower
❓ Frequently Asked Questions — Comparing These Plants
Physostegia
What are the light requirements for Physostegia?
Physostegia prefers full sun, which translates to at least six hours of direct sunlight per day. In hotter climates, some afternoon shade can be beneficial to prevent scorching. Insufficient light can lead to leggy growth and reduced flowering. When growing Physostegia indoors (less common), place it near a sunny window, such as a south-facing exposure. Rotate the plant regularly to ensure even light distribution. Be mindful of the intensity of the sunlight, especially during peak summer months, as too much direct sun can also damage the foliage. Observe the plant’s growth and adjust its position accordingly to provide optimal light conditions.
How do I care for Physostegia?
Physostegia thrives in full sun to partial shade, requiring at least six hours of sunlight daily for optimal blooming. Water regularly, especially during dry spells, keeping the soil consistently moist but not waterlogged. Well-draining soil is essential to prevent root rot. Fertilize in early spring with a balanced fertilizer to promote healthy growth and abundant blooms. Deadhead spent flowers to encourage continuous blooming throughout the summer. Physostegia can spread aggressively, so consider planting it in a container or using barriers to control its growth. Divide clumps every few years to maintain vigor and prevent overcrowding. Monitor for common pests like aphids and spider mites, and treat as needed.
How do I propagate Physostegia?
Physostegia can be easily propagated through division. In early spring or fall, carefully dig up the plant and divide the root clump into smaller sections, ensuring each section has healthy roots and shoots. Replant the divisions in well-draining soil. Stem cuttings can also be taken in late spring or early summer. Take 4-6 inch cuttings from new growth, remove the lower leaves, and dip the cut end in rooting hormone. Plant the cuttings in a moist potting mix and keep them humid until rooted. Physostegia does not produce keikis.
Princess Flower
What are the light requirements for Princess Flower?
Princess Flower thrives in bright, indirect sunlight. Ideally, it needs at least 6 hours of sunlight per day to produce abundant blooms. A location near an east- or west-facing window is often suitable indoors. Avoid direct afternoon sun, which can scorch the leaves. If grown outdoors, provide partial shade during the hottest part of the day. Insufficient light can result in fewer blooms and leggy growth. Rotate the plant regularly to ensure even light exposure on all sides. During the winter months, when sunlight is less intense, consider supplementing with artificial grow lights.
How do I care for Princess Flower?
Princess Flower requires well-draining, acidic soil with a pH of 5.5 to 6.5. Water thoroughly when the top inch of soil feels dry, allowing excess water to drain. Fertilize every 2-4 weeks during the growing season (spring to fall) with a balanced fertilizer formulated for flowering plants. Prune regularly to maintain shape and encourage bushier growth and more blooms. Provide bright, indirect sunlight for at least 6 hours a day. Maintain a moderate humidity level, especially indoors. Protect from frost and freezing temperatures. Repot every 1-2 years as needed, using a slightly larger pot. Monitor for pests like aphids and spider mites, and treat promptly if detected. Ensure good air circulation to prevent fungal diseases.
How do I propagate Princess Flower?
Princess Flower can be propagated using stem cuttings. Take 4-6 inch cuttings from new growth in spring or summer. Remove the lower leaves and dip the cut end in rooting hormone. Plant the cuttings in a well-draining potting mix. Keep the soil moist and provide bright, indirect light. Rooting typically occurs within 4-8 weeks. Division can be done when repotting mature plants, carefully separating the root ball. Keikis are not common on Princess Flower.
Last updated: April 24, 2026 — Plant care data reviewed and verified by our editorial team.