Calla vs Physostegia Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Calla
Zantedeschia aethiopica
Zantedeschia aethiopica, commonly known as Calla Lily, is a rhizomatous herbaceous perennial prized for its elegant, trumpet-shaped spathes (modified leaves) that surround a central spadix. While often called a lily, it is not a true lily. It grows from rhizomes, producing large, arrow-shaped, glossy green leaves. It is primarily an outdoor plant, thriving in moist conditions. People grow it for its striking flowers, often used in bouquets and floral arrangements. It can be grown indoors, but requires specific conditions to thrive and may not flower as readily as outdoors.
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.
Quick Plant Comparison
| Feature | Calla | Physostegia |
|---|---|---|
| Light | Bright, indirect light to full sun outdoors. Indoors, provide bright indirect light, ideally near an east- or west-facing window. | Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal flowering. |
| Watering | Every 3-7 days during the growing season, less frequently in winter. | Every 7-10 days outdoors, less frequently if in partial shade or cooler conditions. |
| Humidity | 40-60% | 30-50% |
| Temperature | 18-24°C | 18-27°C |
| Care Level | Moderate | Expert |
| Growth Rate | Moderate | Fast |
| Max Height | Indoors: 0.6-1 meter | Indoors: Rarely exceeds 60 cm (2 feet) and is unlikely to thrive. Outdoors: 60-120 cm (2-4 feet) |
| Pet Safety | ❌ Toxic To Pets | ✅ Safe |
| Soil | Well-draining potting mix rich in organic matter. A mix of peat moss, perlite, and compost is suitable. | Well-drained soil, loamy or sandy soil is best. Amend heavy clay soils with organic matter. |
| Beginner Friendly | With Caution | ❌ No |
| Weekly Maintenance | 10 minutes weekly | Outdoors: 15-30 minutes weekly, including watering, weeding, and pruning. Indoors: 30-45 minutes weekly, including watering, fertilizing, and monitoring for pests and diseases. |
🔬 Botanical Information — Comparing These Plants
Calla
| Scientific Name | Zantedeschia aethiopica |
|---|---|
| Family | Araceae |
| Native To | South Africa |
| Also Known As | Calla Lily, Arum Lily, Trumpet Lily |
| Leaves | Large, arrow-shaped, glossy green leaves. The leaves can be up to 45 cm long and 25 cm wide. Some varieties have speckled or variegated leaves. |
| Flowers | Can flower indoors with proper care, but more reliably flowers outdoors. The 'flower' is a modified leaf called a spathe, which is typically white, but can also be pink, yellow, orange, or purple. The spadix, the yellow spike in the center, is where the true flowers are located. |
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. |
📏 Size & Growth — Plant Comparison
Calla
Physostegia
🌱 Propagation — Comparing Plant Growth
Calla
Methods: Division, Seed
Difficulty: Moderate
Tips: Divide rhizomes in early spring before new growth begins. Ensure each division has at least one eye (bud). Plant divisions in well-draining soil and keep moist. Seed propagation is possible but slower.
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.
✨ Benefits & Features — Comparing Plant Value
Calla
The Calla Lily is not a true lily, but a rhizomatous perennial with a unique spathe and spadix flower structure. Its elegant, trumpet-shaped flowers make it a popular choice for bouquets and floral arrangements. It requires a dormant period in winter to promote flowering in the following season.
- ✓ Aesthetically pleasing flowers.
- ✓ Can be used for cut flower arrangements.
- ✓ Adds a touch of elegance to any room.
- ✓ Can improve mood and reduce stress.
- ✓ Provides a sense of accomplishment through successful care.
- ⚠️ Toxic to pets
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
📅 Maintenance Schedule — Plant Care Comparison
Calla
Physostegia
🌞 Light Requirements
Calla
Bright, indirect light to full sun outdoors. Indoors, provide bright indirect light, ideally near an east- or west-facing window.
Low light tolerant: ❌ No
Physostegia
Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal flowering.
Low light tolerant: ❌ No
💧 Watering Needs
Calla
Keep the soil consistently moist, especially during the growing season. Water thoroughly when the top inch of soil feels dry. Reduce watering in the dormant period. Overwatering can lead to rhizome rot, indicated by yellowing leaves and a foul odor. Underwatering results in wilting and browning leaf tips.
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.
🌡️ Temperature & Humidity
Calla
Temperature: 18-24°C
Humidity: 40-60%
Physostegia
Temperature: 18-27°C
Humidity: 30-50%
🤔 Which Plant Is Right For You?
Calla
Zantedeschia aethiopicaExperienced plant enthusiasts seeking a flowering plant with elegant blooms, willing to provide specific care requirements.
✅ Choose This Plant If...
- You appreciate elegant, trumpet-shaped flowers.
- You can provide bright, indirect light and consistent moisture.
- You are willing to provide a dormant period in winter.
- You are experienced with plant care and can address potential problems.
- You want a plant that can be used for cut flower arrangements.
❌ Skip This Plant If...
- You have pets that may ingest the plant.
- You cannot provide bright light or consistent moisture.
- You are a beginner plant owner.
- You prefer low-maintenance plants.
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.
🎯 Quick Verdict
⚡ Key Differences Between These Plants
Calla is rated Moderate care level, while Physostegia is Expert.
Calla has moderate growth, while Physostegia grows fast.
💡 Pro Tips For Comparing These Plants
Calla Care Tips
Calla Lilies require bright light and consistent moisture. They can be grown indoors, but may not flower as readily as outdoors. Ensure good drainage to prevent rhizome rot. Toxicity to pets is a significant concern. Requires a dormant period in winter.
- Provide a dormant period in winter by reducing watering and keeping the plant in a cool location.
- Ensure good drainage to prevent rhizome rot.
- Fertilize regularly during the growing season to promote flowering.
- Monitor for pests and diseases and treat promptly.
- Provide bright, indirect light for optimal growth and flowering.
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.
⚠️ Common Problems & Solutions — Plant Care Comparison
Calla
Physostegia
❓ Frequently Asked Questions — Comparing These Plants
Calla
What are the light requirements for Calla?
Calla lilies thrive in bright, indirect light. Direct sunlight can scorch their leaves, so avoid placing them in south-facing windows without some form of shading. An east- or west-facing window is ideal, providing ample light without the intensity of direct sun. If you notice the leaves becoming pale or the plant failing to bloom, it may not be receiving enough light. In such cases, consider supplementing with artificial grow lights. During the darker winter months, supplemental lighting is particularly beneficial to maintain healthy growth and encourage future blooms. Ensure the light is diffused to prevent leaf burn. Regular rotation of the plant ensures all sides receive adequate light, preventing uneven growth.
How do I care for Calla?
Calla lilies require bright, indirect light for optimal growth and blooming. Water thoroughly when the top inch of soil feels dry, ensuring proper drainage to prevent root rot. During the growing season (spring and summer), fertilize every 2-4 weeks with a balanced liquid fertilizer diluted to half strength to encourage flowering. Reduce watering and fertilization during the dormant period in fall and winter. Maintain a humidity level of 50-60%. Repot annually in spring using well-draining potting mix. Remove spent flowers to encourage more blooms. Monitor for pests like aphids and spider mites, and treat promptly if detected. Provide support for taller varieties to prevent them from bending. Rotate the plant regularly to ensure even growth and prevent leaning towards the light source. Protect from frost and freezing temperatures.
How do I propagate Calla?
Calla lilies can be propagated by division, stem cuttings (though less common), and keiki (small plantlets that sometimes form on the plant).
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.
Last updated: April 30, 2026 — Plant care data reviewed and verified by our editorial team.