Eryngium vs Honesty Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Eryngium
Eryngium spp.
Eryngium, commonly known as Sea Holly, is a genus of annuals and perennials characterized by their thistle-like appearance and striking metallic blue or silver coloration. Most species are native to coastal or grassland habitats. They feature spiny bracts surrounding cone-shaped flower heads composed of numerous tiny flowers. The foliage is often deeply lobed or divided. Eryngium is primarily grown outdoors for its architectural form, drought tolerance, and long-lasting cut flowers. While some people attempt to grow them indoors, they rarely thrive due to the high light requirements.
Honesty
Lunaria annua
Lunaria annua, commonly known as Honesty, is a biennial plant often grown as an annual. It features heart-shaped, toothed leaves and produces clusters of fragrant, purple or white flowers in spring and summer. The plant is most prized for its distinctive, translucent, papery seedpods that resemble silver coins, hence the common names. It typically grows to a height of 60-90 cm (2-3 feet). While primarily an outdoor plant, it's grown for its ornamental seedpods, which are often dried and used in floral arrangements. It is not naturally an indoor plant and will struggle in typical indoor conditions.
Quick Plant Comparison
| Feature | Eryngium | Honesty |
|---|---|---|
| Light | Full sun (at least 6-8 hours of direct sunlight daily) | Full sun to partial shade |
| Watering | Every 1-2 weeks, depending on weather and soil drainage | Every 7-10 days outdoors, depending on rainfall and temperature |
| Humidity | 30-50% | 40-60% |
| Temperature | 15-25°C | 15-25°C |
| Care Level | Expert | Expert |
| Growth Rate | Moderate | Fast |
| Max Height | 0.3-1.5 meters (outdoors); significantly smaller and less vigorous indoors | N/A (primarily grown outdoors) |
| Pet Safety | ❌ Toxic To Pets | ❌ Toxic To Pets |
| Soil | Well-drained, sandy or gravelly soil | Well-draining soil, such as a mix of garden soil, compost, and perlite |
| Beginner Friendly | ❌ No | ❌ No |
| Weekly Maintenance | 10 minutes weekly (outdoors) | 10 minutes weekly (weeding, watering) |
🔬 Botanical Information — Comparing These Plants
Eryngium
| Scientific Name | Eryngium spp. |
|---|---|
| Family | Apiaceae |
| Native To | Varies by species; native to Europe, North Africa, Asia, North and South America |
| Also Known As | Sea Holly, Eryngo |
| Leaves | The leaves of Eryngium are often deeply lobed or divided, with a leathery texture. The color can range from green to blue-green, depending on the species and cultivar. Some species have spiny margins on the leaves. |
| Flowers | Eryngium rarely flowers indoors. Outdoors, it produces cone-shaped flower heads surrounded by spiny bracts. The flowers are typically blue, silver, or white and are composed of numerous tiny individual flowers. |
Honesty
| Scientific Name | Lunaria annua |
|---|---|
| Family | Brassicaceae |
| Native To | Southeastern Europe and Western Asia |
| Also Known As | Honesty, Silver Dollar Plant, Money Plant, Moonwort |
| Leaves | Heart-shaped, toothed leaves that are typically 5-15 cm (2-6 inches) long. The leaves are medium green and have a slightly rough texture. |
| Flowers | Produces clusters of fragrant, purple or white flowers in spring and summer. The flowers are small, about 2 cm (0.75 inches) in diameter, and have four petals. |
📏 Size & Growth — Plant Comparison
Eryngium
Honesty
🌱 Propagation — Comparing Plant Growth
Eryngium
Methods: Seed, Root cuttings, Division
Difficulty: Moderate
Tips: Sow seeds in fall or early spring. Root cuttings should be taken in late winter. Division is best done in spring or fall.
Honesty
Methods: Seed
Difficulty: Easy
Tips: Sow seeds directly into the garden in spring or fall. Seeds can also be started indoors 6-8 weeks before the last frost. Ensure good soil contact and keep the soil moist until germination.
✨ Benefits & Features — Comparing Plant Value
Eryngium
Eryngium stands out with its metallic blue or silver coloration and thistle-like appearance, making it a striking addition to any garden. Its drought tolerance and ability to attract pollinators further enhance its appeal.
- ✓ Attracts pollinators like bees and butterflies.
- ✓ Provides visual interest with its unique texture and color.
- ✓ Drought-tolerant, reducing water consumption.
- ✓ Long-lasting cut flowers for arrangements.
- ✓ Adds architectural structure to the garden.
- ⚠️ Toxic to pets
Honesty
The translucent, papery seedpods are its most distinctive feature, giving it the common name 'Silver Dollar Plant'. The plant's ability to self-seed readily allows for natural propagation and a continuous display in the garden. Its fragrant flowers attract pollinators, contributing to garden biodiversity.
- ✓ Provides ornamental seedpods for dried arrangements.
- ✓ Attracts pollinators to the garden.
- ✓ Adds visual interest to the garden in fall and winter.
- ✓ Low-maintenance once established.
- ✓ Fragrant flowers enhance the garden experience.
- ⚠️ Toxic to pets
📅 Maintenance Schedule — Plant Care Comparison
Eryngium
Honesty
🌞 Light Requirements
Eryngium
Full sun (at least 6-8 hours of direct sunlight daily)
Low light tolerant: ❌ No
Honesty
Full sun to partial shade
Low light tolerant: ❌ No
💧 Watering Needs
Eryngium
Water deeply when the soil is dry to the touch. Avoid overwatering, as Eryngium prefers well-drained soil. Overwatering can lead to root rot. Underwatering will cause wilting and browning of leaves.
Honesty
Water regularly, especially during dry periods. Avoid overwatering, which can lead to root rot. Allow the soil to dry slightly between waterings. Signs of underwatering include wilting leaves, while overwatering can cause yellowing and leaf drop.
🌡️ Temperature & Humidity
Eryngium
Temperature: 15-25°C
Humidity: 30-50%
Honesty
Temperature: 15-25°C
Humidity: 40-60%
🤔 Which Plant Is Right For You?
Eryngium
Eryngium spp.Experienced gardeners seeking a drought-tolerant and visually striking plant for sunny outdoor gardens.
✅ Choose This Plant If...
- You want a drought-tolerant plant for a sunny garden.
- You are looking for a unique and architectural plant.
- You want to attract pollinators to your garden.
- You need long-lasting cut flowers.
- You appreciate plants with a metallic blue or silver hue.
❌ Skip This Plant If...
- You have pets that might ingest the plant.
- You cannot provide full sun.
- You are looking for an easy-to-grow indoor plant.
Honesty
Lunaria annuaGardeners who want to add unique, ornamental seedpods to their garden and dried flower arrangements.
✅ Choose This Plant If...
- You love unique dried flower arrangements and want to grow your own materials.
- You have a sunny garden spot and enjoy cottage-style gardens.
- You want to attract pollinators to your garden with its fragrant flowers.
- You enjoy the sound of rustling seedpods in the breeze.
- You want a low-maintenance plant that adds visual interest to your garden in the fall and winter.
❌ Skip This Plant If...
- You have pets that might ingest the plant, as it is toxic.
- You don't have a sunny outdoor space.
- You are looking for a plant that thrives indoors.
🎯 Quick Verdict
⚡ Key Differences Between These Plants
Eryngium needs full sun (at least 6-8 hours of direct sunlight daily), while Honesty prefers full sun to partial shade.
Eryngium has moderate growth, while Honesty grows fast.
💡 Pro Tips For Comparing These Plants
Eryngium Care Tips
Eryngium is primarily an outdoor plant and requires full sun and well-drained soil. Indoor cultivation is challenging due to the high light requirements and difficulty replicating outdoor conditions. It is prone to root rot if overwatered. Expect significantly reduced growth and flowering indoors.
- Ensure excellent drainage to prevent root rot.
- Provide full sun for optimal growth and flowering.
- Avoid over-fertilizing, as this can lead to leggy growth.
- Cut back spent flower heads to encourage more blooms.
- Protect from strong winds, especially taller varieties.
Honesty Care Tips
Honesty is primarily an outdoor plant and is challenging to grow indoors due to its high light requirements. It needs full sun to thrive and produce abundant seedpods. Indoor cultivation is not recommended unless you can provide very bright light and proper ventilation.
- Allow seedpods to dry on the plant before harvesting for best results.
- Provide well-draining soil to prevent root rot.
- Water regularly during dry periods, especially when plants are young.
- Deadhead spent flowers to encourage more seedpod production.
- Protect from strong winds, which can damage the seedpods.
⚠️ Common Problems & Solutions — Plant Care Comparison
Eryngium
Honesty
❓ Frequently Asked Questions — Comparing These Plants
Eryngium
What are the light requirements for Eryngium?
Eryngium requires at least 6-8 hours of direct sunlight per day to thrive and produce vibrant blooms. Insufficient light can result in leggy growth, reduced flowering, and dull coloration. Choose a location in your garden or on your patio where it will receive ample sunlight throughout the day.
How do I care for Eryngium?
Eryngium thrives in full sun and well-drained soil. Water deeply but infrequently, allowing the soil to dry out between waterings. Avoid overwatering, which can lead to root rot. Fertilize sparingly, using a balanced fertilizer in early spring to promote healthy growth and abundant blooms.
How do I propagate Eryngium?
Eryngium can be propagated by seed, division, or root cuttings. Division is best done in spring or fall. Carefully dig up the plant and separate the roots into smaller clumps. Replant the divisions in well-drained soil.
Honesty
What are the light requirements for Honesty?
Honesty prefers partial shade, especially in hotter climates. While it can tolerate full sun, too much direct sunlight can scorch the leaves and fade the flowers. In cooler regions, Honesty can thrive in full sun, but afternoon shade is still beneficial. When grown indoors, place Honesty near a bright, east-facing window that receives morning sun. Avoid south-facing windows that provide intense afternoon sun. If you don’t have access to natural light, you can supplement with artificial grow lights. Ensure the lights are positioned about 12-18 inches above the plant and provide at least 14-16 hours of light per day. Insufficient light can lead to leggy growth and reduced flowering.
How do I care for Honesty?
Honesty is relatively easy to care for, making it a great choice for beginner gardeners. It thrives in well-draining soil and prefers partial shade, although it can tolerate full sun in cooler climates. Water regularly, especially during dry periods, but avoid overwatering, which can lead to root rot. Fertilize sparingly, using a balanced fertilizer in spring to promote healthy growth and flowering. Deadhead spent flowers to encourage further blooming. Honesty is typically grown as a biennial, meaning it completes its life cycle in two years. In the first year, it focuses on vegetative growth, and in the second year, it flowers and produces seedpods. After the seedpods mature and dry, they can be harvested for decorative purposes. Honesty self-seeds readily, so be prepared for new plants to appear in subsequent years. Pruning is not typically required, but you can trim back the plant after flowering to maintain its shape.
How do I propagate Honesty?
Honesty can be propagated by seeds or by division. To propagate by seeds, collect the seeds from mature seedpods and sow them in spring or fall. Sow seeds directly into the garden or start them indoors in seed trays. Keep the soil moist and provide bright, indirect light. To propagate by division, carefully dig up the plant in spring or fall and divide the root ball into several sections. Replant the divisions in fresh, well-draining soil. Ensure each division has healthy roots and shoots. Division is not always successful, as Honesty can be sensitive to root disturbance. Stem cuttings and keiki propagation are not applicable to Honesty.
Last updated: May 10, 2026 — Plant care data reviewed and verified by our editorial team.