Physostegia vs Pimpernel 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.
Pimpernel
Lysimachia arvensis
Scarlet Pimpernel is a low-growing annual plant typically found in fields, gardens, and disturbed areas. It's characterized by its small, oval-shaped leaves and distinctive bright scarlet (though sometimes pink, orange, or blue) flowers that open only when the sun is shining. The plant rarely exceeds 30 cm in height. While historically used in herbal medicine, it's now primarily considered a weed. It is not typically grown indoors due to its preference for full sun and its weedy nature.
Quick Plant Comparison
| Feature | Physostegia | Pimpernel |
|---|---|---|
| Light | Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal flowering. | Full sun |
| Watering | Every 7-10 days outdoors, less frequently if in partial shade or cooler conditions. | Every 2-3 days in hot weather, 5-7 days in cooler weather, depending on soil dryness. |
| Humidity | 30-50% | 30-50% |
| Temperature | 18-27°C | 15-25°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) | 10-30 cm |
| 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 soil, sandy or loamy soil is preferred. |
| 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. | 5 minutes weekly (weeding, removing dead foliage) |
🔬 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. |
Pimpernel
| Scientific Name | Lysimachia arvensis |
|---|---|
| Family | Primulaceae |
| Native To | Europe, North Africa, and parts of Asia; naturalized worldwide |
| Also Known As | Scarlet Pimpernel, Red Pimpernel, Shepherd's Weatherglass, Poor Man's Weatherglass |
| Leaves | Small, oval-shaped leaves, typically 1-2 cm long, arranged in opposite pairs along the stem. The leaves are a light green color and have smooth edges. |
| Flowers | Flowers are small, about 1 cm in diameter, and typically bright scarlet, though pink, orange, and blue varieties exist. They open only when the sun is shining and close in response to cloudy weather or impending rain. Flowering occurs primarily in spring and summer. It is unlikely to flower indoors. |
📏 Size & Growth — Plant Comparison
Physostegia
Pimpernel
🌱 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.
Pimpernel
Methods: Seed
Difficulty: Easy
Tips: Sow seeds directly into the soil in spring or fall. Seeds germinate readily in warm, sunny conditions.
✨ 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
Pimpernel
The flowers of Scarlet Pimpernel are known to close in response to impending rain or cloudy weather, earning it the name 'Shepherd's Weatherglass'. The flower color can vary, with scarlet being the most common, but pink, orange, and blue varieties also exist.
- ✓ Attracts pollinators
- ✓ Provides ground cover
- ✓ Historically used for weather prediction
- ✓ Adds color to the garden
- ✓ Self-seeds easily
- ⚠️ Toxic to pets
📅 Maintenance Schedule — Plant Care Comparison
Physostegia
Pimpernel
🌞 Light Requirements
Physostegia
Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal flowering.
Low light tolerant: ❌ No
Pimpernel
Full sun
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.
Pimpernel
Water thoroughly when the top inch of soil is dry. Avoid overwatering, which can lead to root rot. Allow the soil to dry slightly between waterings. Signs of overwatering include yellowing leaves and a soggy soil surface. Underwatering will cause wilting and dry, brittle leaves.
🌡️ Temperature & Humidity
Physostegia
Temperature: 18-27°C
Humidity: 30-50%
Pimpernel
Temperature: 15-25°C
Humidity: 30-50%
🤔 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.
Pimpernel
Lysimachia arvensisGardeners looking for a low-maintenance ground cover in a sunny location, aware of its potential to spread.
✅ Choose This Plant If...
- You want a low-growing ground cover for a sunny area.
- You are interested in a plant with a historical connection to weather forecasting.
- You want to attract pollinators to your garden.
- You have a well-draining, sandy soil.
- You are looking for a plant that self-seeds easily.
❌ Skip This Plant If...
- You have pets that might ingest it.
- You want a plant that thrives indoors.
- You are looking for a low-maintenance houseplant.
🎯 Quick Verdict
⚡ Key Differences Between These Plants
Physostegia has fast growth, while Pimpernel grows fast.
💡 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.
Pimpernel Care Tips
Scarlet Pimpernel is primarily an outdoor plant and is very difficult to cultivate indoors. It requires full sun and well-draining soil. It is considered a weed in many areas and can spread rapidly. Indoor cultivation is not recommended.
- Ensure well-draining soil to prevent root rot.
- Provide full sun for optimal flowering.
- Avoid over-fertilizing, as this can lead to excessive foliage growth.
- Monitor for aphids and treat promptly.
- Allow the plant to self-seed for continuous growth.
⚠️ Common Problems & Solutions — Plant Care Comparison
Physostegia
Pimpernel
❓ 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.
Pimpernel
What are the light requirements for Pimpernel?
Pimpernel generally prefers partial sunlight, receiving about 4-6 hours of direct sunlight per day. However, some varieties can tolerate full sun, especially in cooler climates. Insufficient light can lead to leggy growth and reduced flowering. Indoors, place Pimpernel near a sunny window, such as an east- or west-facing window. Rotate the plant regularly to ensure even light exposure. If natural light is insufficient, supplement with artificial grow lights. Be mindful of intense afternoon sun, which can scorch the leaves, particularly in hot climates.
How do I care for Pimpernel?
Pimpernel thrives in well-draining soil and prefers partial to full sunlight, depending on the specific species. Water regularly, allowing the soil to dry slightly between waterings. Fertilize monthly during the growing season (spring and summer) with a balanced liquid fertilizer to encourage abundant blooming. Prune back spent flowers to promote further flowering. Provide adequate air circulation to prevent fungal diseases. Pimpernel can tolerate a range of temperatures but prefers moderate conditions. Repot in spring if the plant becomes root-bound. Monitor for pests like aphids and spider mites and treat accordingly.
How do I propagate Pimpernel?
Pimpernel can be easily propagated through stem cuttings or division.
Last updated: April 30, 2026 — Plant care data reviewed and verified by our editorial team.