Lobelia Cardinalis vs Myrtle Spurge Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Lobelia Cardinalis
Lobelia cardinalis
Lobelia cardinalis, the Cardinal flower, is a striking herbaceous perennial native to North America. It features vibrant red, tubular flowers arranged on tall spikes, reaching heights of 2-4 feet. The plant has lance-shaped, green leaves that provide a lush backdrop to the brilliant blooms. It thrives in moist, well-drained soil and prefers partial shade to full sun. Cardinal flowers are primarily grown for their showy flowers, which attract hummingbirds and butterflies, making them a popular choice for gardens and naturalized areas. While it can be grown in containers, it is primarily an outdoor plant and may struggle indoors.
Myrtle Spurge
Euphorbia myrsinites
Myrtle Spurge is a succulent, low-growing perennial characterized by its sprawling habit and blue-gray, spirally arranged leaves. It typically reaches a height of 6-12 inches and spreads up to 24 inches wide. It is primarily grown as an ornamental ground cover in rock gardens or dry landscapes. It produces small, inconspicuous yellowish-green flowers in spring, followed by seed capsules. This plant is naturally an outdoor plant and struggles indoors due to its high light requirements and need for well-draining soil.
Quick Plant Comparison
| Feature | Lobelia Cardinalis | Myrtle Spurge |
|---|---|---|
| Light | Partial shade to full sun (at least 6 hours of direct sunlight) | Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal growth. |
| Watering | Every 2-3 days, depending on weather and soil drainage | Every 2-4 weeks, depending on weather and soil drainage. |
| Humidity | 40-60% | 20-40% |
| Temperature | 15-25°C | 15-25°C |
| Care Level | Expert | Expert |
| Growth Rate | Moderate | Moderate |
| Max Height | 0.6-1.2 meters (2-4 feet) | 6-12 inches (outdoor) |
| Pet Safety | ❌ Toxic To Pets | ❌ Toxic To Pets |
| Soil | Rich, well-drained soil with plenty of organic matter | Well-draining, sandy or gravelly soil. Avoid heavy clay soils. |
| Beginner Friendly | ❌ No | ❌ No |
| Weekly Maintenance | 15 minutes weekly | 15 minutes monthly (weeding, pruning) |
🔬 Botanical Information — Comparing These Plants
Lobelia Cardinalis
| Scientific Name | Lobelia cardinalis |
|---|---|
| Family | Campanulaceae |
| Native To | North America |
| Also Known As | Cardinal flower, Red lobelia |
| Leaves | Lance-shaped, medium green leaves with serrated edges. Leaves are typically 7-15 cm long and arranged alternately along the stem. |
| Flowers | Flowers are bright red, tubular, and arranged in a spike-like raceme. They bloom from mid-summer to early fall. It is highly unlikely to flower indoors due to light requirements. |
Myrtle Spurge
| Scientific Name | Euphorbia myrsinites |
|---|---|
| Family | Euphorbiaceae |
| Native To | Mediterranean region (Southern Europe and North Africa) |
| Also Known As | Myrtle Spurge, Donkey Spurge, Creeping Spurge, Glaucous Spurge |
| Leaves | Succulent, blue-gray, lance-shaped leaves arranged in a spiral pattern around the stems. Leaves are typically 1-2 inches long. |
| Flowers | Produces small, inconspicuous yellowish-green flowers in spring. Rarely flowers indoors. |
📏 Size & Growth — Plant Comparison
Lobelia Cardinalis
Myrtle Spurge
🌱 Propagation — Comparing Plant Growth
Lobelia Cardinalis
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.
Myrtle Spurge
Methods: Seed, Stem cuttings
Difficulty: Moderate
Tips: Take stem cuttings in spring or summer, allow the cut end to callous over for a few days, and then plant in well-draining soil. Wear gloves to avoid skin irritation from the sap.
✨ Benefits & Features — Comparing Plant Value
Lobelia Cardinalis
The vibrant red color and tubular shape of the flowers are specifically adapted to attract hummingbirds. It is a native plant that supports local ecosystems and provides habitat for wildlife.
- ✓ Attracts pollinators (hummingbirds, butterflies)
- ✓ Adds vibrant color to the garden
- ✓ Provides habitat for wildlife
- ✓ Native plant supports local ecosystems
- ✓ Can be used in cut flower arrangements
- ⚠️ Toxic to pets
Myrtle Spurge
The spirally arranged, blue-gray leaves give it a distinctive appearance. The milky sap is toxic and can cause skin irritation.
- ✓ Drought tolerance reduces water usage.
- ✓ Provides visual interest with its unique foliage.
- ✓ Low maintenance once established.
- ✓ Attracts pollinators.
- ✓ Controls erosion on slopes.
- ⚠️ Toxic to pets
📅 Maintenance Schedule — Plant Care Comparison
Lobelia Cardinalis
Myrtle Spurge
🌞 Light Requirements
Lobelia Cardinalis
Partial shade to full sun (at least 6 hours of direct sunlight)
Low light tolerant: ❌ No
Myrtle Spurge
Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal growth.
Low light tolerant: ❌ No
💧 Watering Needs
Lobelia Cardinalis
Keep the soil consistently moist, especially during hot weather. Water deeply when the top inch of soil feels dry. Overwatering can lead to root rot, indicated by yellowing leaves and a musty smell. Underwatering results in wilting and dry, crispy leaves.
Myrtle Spurge
Water deeply but infrequently, allowing the soil to dry out completely between waterings. Overwatering can lead to root rot. Signs of underwatering include shriveled leaves. Signs of overwatering include yellowing leaves and a mushy stem.
🌡️ Temperature & Humidity
Lobelia Cardinalis
Temperature: 15-25°C
Humidity: 40-60%
Myrtle Spurge
Temperature: 15-25°C
Humidity: 20-40%
🤔 Which Plant Is Right For You?
Lobelia Cardinalis
Lobelia cardinalisGardeners looking to attract hummingbirds and butterflies to their moist, partially shaded gardens.
✅ Choose This Plant If...
- You want to attract hummingbirds to your garden.
- You have a moist, partially shaded area in your yard.
- You appreciate vibrant red flowers.
- You enjoy native North American plants.
- You want a plant that adds vertical interest to your garden.
❌ Skip This Plant If...
- You have pets that might ingest the plant.
- You have a dry garden.
- You are looking for a low-maintenance indoor plant.
Myrtle Spurge
Euphorbia myrsinitesExperienced gardeners looking for a drought-tolerant ground cover in sunny, well-drained locations.
✅ Choose This Plant If...
- You need a drought-tolerant ground cover for a sunny area.
- You appreciate the unique blue-gray foliage.
- You are an experienced gardener familiar with handling toxic plants.
- You want a low-maintenance plant once established.
- You have a rock garden or xeriscape landscape.
❌ Skip This Plant If...
- You have pets or small children who may ingest the plant.
- You are a beginner gardener.
- You do not have a sunny outdoor space.
- You are sensitive to latex or have skin allergies.
🎯 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
Lobelia Cardinalis Care Tips
Lobelia cardinalis is primarily an outdoor plant that requires consistent moisture and partial to full sun. Indoor cultivation is challenging due to the need for high light levels and humidity. It is prone to root rot if overwatered and requires regular fertilization during the growing season. It is also toxic to pets.
- Provide consistent moisture, especially during hot weather.
- Deadhead spent flowers to encourage more blooms.
- Divide clumps every few years to prevent overcrowding.
- Protect from slugs and snails.
- Mulch around the base of the plant to retain moisture and suppress weeds.
Myrtle Spurge Care Tips
Myrtle Spurge is an outdoor plant that requires full sun and well-draining soil. It is not suitable for indoor growing due to its high light requirements and potential for toxicity. It is drought-tolerant and relatively low-maintenance once established, but requires careful handling due to its toxic sap.
- Always wear gloves and eye protection when handling Myrtle Spurge.
- Remove seed heads to prevent unwanted spread.
- Ensure excellent drainage to prevent root rot.
- Water deeply but infrequently.
- Provide full sun for optimal growth and color.
⚠️ Common Problems & Solutions — Plant Care Comparison
Lobelia Cardinalis
Myrtle Spurge
❓ Frequently Asked Questions — Comparing These Plants
Lobelia Cardinalis
What are the light requirements for Lobelia Cardinalis?
Lobelia Cardinalis prefers bright, indirect light. While it can tolerate some morning sun, intense afternoon sun can scorch the leaves, especially in hotter climates. When grown indoors, place the plant near an east-facing or west-facing window where it will receive ample light without direct exposure. If you don’t have access to natural light, consider using a grow light to supplement its needs. Insufficient light can lead to leggy growth and reduced flowering. Rotate the plant regularly to ensure even light exposure on all sides. Watch for signs of overexposure, such as bleached or burned leaves, and adjust the plant’s location accordingly.
How do I care for Lobelia Cardinalis?
Lobelia Cardinalis thrives in consistently moist soil, ideally rich in organic matter. Water regularly, especially during dry periods, ensuring the soil doesn’t dry out completely. Provide bright, indirect light; direct sunlight can scorch the leaves. Fertilize every 2-4 weeks during the growing season (spring and summer) with a balanced liquid fertilizer, diluted to half strength. Deadhead spent flowers to encourage continued blooming. Maintain a humid environment, especially if growing indoors; consider using a humidifier or placing the plant on a pebble tray filled with water. Protect from frost in colder climates, either by bringing it indoors or providing adequate winter protection. Repot in spring if the plant becomes root-bound. Monitor for pests such as aphids and spider mites, and treat promptly if necessary. Propagate by seed, division, or stem cuttings.
How do I propagate Lobelia Cardinalis?
Lobelia Cardinalis can be propagated by division, stem cuttings, or seeds. For division, carefully separate the plant into smaller clumps in early spring, ensuring each clump has roots and foliage. Replant the divisions in moist, well-draining soil. For stem cuttings, take 4-6 inch cuttings from healthy stems in spring or summer. Remove the lower leaves and place the cuttings in water or moist potting mix until roots develop. Once rooted, transplant into pots. Seeds can be sown indoors in early spring or directly outdoors after the last frost. Keep the soil consistently moist until germination.
Myrtle Spurge
What are the light requirements for Myrtle Spurge?
Myrtle Spurge thrives in bright, direct sunlight. Aim for at least 6 hours of sunlight per day. An east- or south-facing window is ideal. If grown outdoors, choose a location that receives full sun. Insufficient light can lead to etiolation, where the plant stretches towards the light source, resulting in weak, leggy growth. Rotate the plant regularly to ensure even light exposure on all sides. In regions with intense summer sun, provide some afternoon shade to prevent scorching. Supplement with grow lights if natural light is limited, particularly during winter months.
How do I care for Myrtle Spurge?
Myrtle Spurge requires well-draining soil, such as a cactus or succulent mix, to prevent root rot. Water thoroughly when the soil is completely dry, typically every 2-4 weeks, depending on environmental conditions. Provide bright, direct sunlight for at least 6 hours a day; however, protect it from intense afternoon sun in hot climates. Fertilize sparingly, only during the growing season (spring and summer), using a balanced, diluted succulent fertilizer. Prune dead or damaged leaves to maintain its appearance. Be extremely cautious of the milky sap, which can cause skin irritation. Wear gloves when handling. Avoid overwatering, especially during winter dormancy.
How do I propagate Myrtle Spurge?
Myrtle Spurge can be propagated through stem cuttings, leaf cuttings, or offsets. For stem cuttings, allow the cut end to callous over for a few days before planting in well-draining soil. Rooting hormone can aid in the process. Leaf cuttings can be placed on top of well-draining soil and misted occasionally. Offsets, or small plantlets that grow around the base of the mother plant, can be carefully separated and potted individually. Wear gloves when handling cuttings to avoid skin irritation from the sap. Provide bright, indirect light and maintain consistent moisture until roots develop. Propagation is best done during the growing season (spring or summer).
Last updated: May 6, 2026 — Plant care data reviewed and verified by our editorial team.