Cardinal Flower vs Pimpernel Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Cardinal Flower
Lobelia cardinalis
Lobelia cardinalis, or Cardinal Flower, is a striking herbaceous perennial native to North America. It features vibrant, intensely red flowers arranged in tall, erect spikes that can reach up to 4 feet in height. The plant has lance-shaped, green leaves that provide a backdrop for the brilliant blooms. Cardinal flowers are primarily grown for their ornamental value, attracting hummingbirds and butterflies to gardens. While occasionally attempted indoors, it is challenging to replicate the plant's natural habitat, making it primarily an outdoor plant.
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 | Cardinal Flower | Pimpernel |
|---|---|---|
| Light | Full sun to partial shade | Full sun |
| Watering | 2-3 times per week, depending on weather and soil drainage | Every 2-3 days in hot weather, 5-7 days in cooler weather, depending on soil dryness. |
| Humidity | 40-60% | 30-50% |
| Temperature | 15-27°C | 15-25°C |
| Care Level | Expert | Expert |
| Growth Rate | Moderate | Fast |
| Max Height | Outdoors: 0.6-1.2 meters (2-4 feet). Indoors: rarely exceeds 0.6 meters (2 feet) and often struggles. | 10-30 cm |
| Pet Safety | ❌ Toxic To Pets | ❌ Toxic To Pets |
| Soil | Rich, well-drained, consistently moist soil. A mix of garden soil, compost, and peat moss is suitable. | Well-draining soil, sandy or loamy soil is preferred. |
| Beginner Friendly | ❌ No | ❌ No |
| Weekly Maintenance | 30 minutes weekly during the growing season. | 5 minutes weekly (weeding, removing dead foliage) |
🔬 Botanical Information — Comparing These Plants
Cardinal Flower
| Scientific Name | Lobelia cardinalis |
|---|---|
| Family | Campanulaceae |
| Native To | North America |
| Also Known As | Cardinal Flower, Red Lobelia |
| Leaves | Lance-shaped, toothed, green leaves arranged alternately along the stem. Leaves are typically 5-15 cm long. |
| Flowers | Does not typically flower indoors. Outdoors, it produces vibrant red, tubular flowers arranged in tall spikes during the summer months. Each flower is about 2-4 cm long. |
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
Cardinal Flower
Pimpernel
🌱 Propagation — Comparing Plant Growth
Cardinal Flower
Methods: Seed, Division, Stem cuttings
Difficulty: Moderate
Tips: For seeds, cold stratify for 30 days before sowing. Divide clumps in spring or fall. Take stem cuttings in late spring and root in moist soil.
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
Cardinal Flower
The Cardinal Flower is known for its brilliant red flowers and its ability to attract hummingbirds. Its tall, erect flower spikes make it a striking addition to any garden.
- ✓ Attracts pollinators like hummingbirds and butterflies.
- ✓ Adds vibrant color to the garden.
- ✓ Native plant supports local ecosystems.
- ✓ Can be used in cut flower arrangements.
- ✓ Provides visual interest with its tall flower spikes.
- ⚠️ Toxic to pets
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
Cardinal Flower
Pimpernel
🌞 Light Requirements
Cardinal Flower
Full sun to partial shade
Low light tolerant: ❌ No
Pimpernel
Full sun
Low light tolerant: ❌ No
💧 Watering Needs
Cardinal Flower
Requires consistently moist soil. Water deeply when the top inch of soil feels dry. Avoid letting the soil dry out completely, especially during hot weather. Overwatering can lead to root rot, so ensure good drainage. Signs of underwatering include wilting leaves and dry soil. Overwatering signs 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
Cardinal Flower
Temperature: 15-27°C
Humidity: 40-60%
Pimpernel
Temperature: 15-25°C
Humidity: 30-50%
🤔 Which Plant Is Right For You?
Cardinal Flower
Lobelia cardinalisGardeners who want to attract hummingbirds and butterflies to their moist, shady gardens.
✅ Choose This Plant If...
- You want to attract hummingbirds to your garden.
- You have a consistently moist area in your garden.
- You appreciate vibrant red flowers.
- You want a native North American plant.
- You are an experienced gardener willing to provide specific care.
❌ Skip This Plant If...
- You have pets that might ingest the plant.
- You struggle to maintain consistently moist soil.
- You want a low-maintenance plant.
- You are looking for an easy 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
Cardinal Flower needs full sun to partial shade, while Pimpernel prefers full sun.
Cardinal Flower has moderate growth, while Pimpernel grows fast.
💡 Pro Tips For Comparing These Plants
Cardinal Flower Care Tips
Cardinal Flower is best suited for outdoor gardens with moist soil and partial shade. Indoor cultivation is challenging due to the need for high humidity, consistent moisture, and specific light conditions. It requires careful monitoring and is prone to root rot if overwatered.
- Ensure consistent moisture, especially during hot weather.
- Provide afternoon shade in hotter climates to prevent scorching.
- Deadhead spent flowers to encourage more blooms.
- Protect from slugs and snails.
- Divide clumps every few years to maintain vigor.
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
Cardinal Flower
Pimpernel
❓ Frequently Asked Questions — Comparing These Plants
Cardinal Flower
What are the light requirements for Cardinal Flower?
Cardinal Flower prefers partial to full sun, needing at least 6 hours of sunlight daily for optimal blooming. In hotter climates, providing afternoon shade is crucial to prevent leaf scorch and wilting. A location with morning sun and afternoon shade is ideal. Insufficient light can lead to leggy growth and reduced flowering. When grown indoors (less common but possible), place near a bright, east-facing window or supplement with grow lights. Rotate the plant regularly to ensure even light exposure. Monitor the plant for signs of stress, such as pale leaves, which may indicate insufficient light. Adjust the plant’s location accordingly.
How do I care for Cardinal Flower?
Cardinal Flower thrives in moist, well-drained soil and prefers partial to full sun, though afternoon shade is beneficial in hot climates. Water regularly, especially during dry spells, keeping the soil consistently moist but not waterlogged. Fertilize in spring with a balanced, slow-release fertilizer or a liquid feed every few weeks during the growing season to encourage abundant blooming. Deadhead spent flowers to prolong the blooming period. Protect from slugs and snails. Mulch around the base of the plant to retain moisture and suppress weeds. Divide clumps every few years to maintain vigor. Provide good air circulation to prevent fungal diseases. Monitor for pests like aphids. Cardinal Flower benefits from consistent moisture and nutrient availability for optimal growth.
How do I propagate Cardinal Flower?
Cardinal Flower can be propagated by division, stem cuttings, and keiki.
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.