Flowering Kale vs Perennial Flax Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Flowering Kale
Brassica oleracea var. acephala
Flowering kale is a cool-season biennial grown as an annual for its vibrant, colorful foliage. It is not grown for edible leaves like its close relative, edible kale. The plant forms a rosette of ruffled or frilly leaves in shades of white, pink, purple, or red, surrounded by outer green leaves. It is primarily an outdoor plant, thriving in cooler temperatures and full sun. People grow it for its ornamental value, adding color and texture to gardens and containers during the fall and winter months.
Perennial Flax
Linum perenne
Perennial Flax (Linum perenne) is a herbaceous perennial known for its delicate, airy appearance and profuse display of sky-blue flowers. It typically grows to a height of 30-60 cm. The plant features slender stems and narrow, lance-shaped leaves. While primarily an outdoor plant, it is grown for its ornamental value in gardens and meadows, attracting pollinators. The flowers are short-lived, opening in the morning and closing by afternoon, but the plant produces a continuous succession of blooms throughout the flowering season. It is not naturally an indoor plant.
Quick Plant Comparison
| Feature | Flowering Kale | Perennial Flax |
|---|---|---|
| Light | Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal color development. | Full sun |
| Watering | Every 3-7 days, depending on weather and soil drainage. | Every 7-10 days, depending on weather and soil drainage |
| Humidity | 40-60% | 30-50% |
| Temperature | 4-18°C | 15-24°C |
| Care Level | Expert | Expert |
| Growth Rate | Moderate | Moderate |
| Max Height | 20-40 cm | N/A (Outdoor plant, not suitable for indoor growing) |
| Pet Safety | ❌ Toxic To Pets | ❌ Toxic To Pets |
| Soil | Well-draining potting mix or garden soil enriched with organic matter. | Well-draining, sandy or loamy soil |
| Beginner Friendly | ❌ No | ❌ No |
| Weekly Maintenance | 5 minutes weekly | 5 minutes weekly |
🔬 Botanical Information — Comparing These Plants
Flowering Kale
| Scientific Name | Brassica oleracea var. acephala |
|---|---|
| Family | Brassicaceae |
| Native To | Europe |
| Also Known As | Flowering Kale, Ornamental Kale, Ornamental Cabbage |
| Leaves | The leaves of flowering kale are broad and ruffled or frilly, depending on the variety. They can range in size from 15-30 cm in diameter. The outer leaves are typically green, while the inner leaves display vibrant colors such as white, pink, purple, or red. The texture is often slightly waxy. |
| Flowers | Flowering kale may produce small yellow flowers if it overwinters and bolts in the spring. However, it is primarily grown for its foliage, and the flowers are not particularly showy. Flowering is often considered undesirable as it signals the end of the plant's ornamental display. |
Perennial Flax
| Scientific Name | Linum perenne |
|---|---|
| Family | Linaceae |
| Native To | Europe, North Africa, Asia |
| Also Known As | Perennial Flax, Blue Flax, Flax |
| Leaves | Narrow, lance-shaped leaves, typically blue-green in color, arranged alternately along the stems. |
| Flowers | Flowers are typically sky-blue, about 2.5 cm in diameter, with five petals. They open in the morning and close by afternoon. Rarely flowers indoors. |
📏 Size & Growth — Plant Comparison
Flowering Kale
Perennial Flax
🌱 Propagation — Comparing Plant Growth
Flowering Kale
Methods: Seed
Difficulty: Easy
Tips: Sow seeds indoors 6-8 weeks before the last expected frost or directly outdoors in late summer for fall/winter color. Provide consistent moisture and light for germination.
Perennial Flax
Methods: Seed, Division
Difficulty: Easy
Tips: Sow seeds in spring or fall. Divide established plants in spring or fall. Ensure good drainage for successful propagation.
✨ Benefits & Features — Comparing Plant Value
Flowering Kale
Flowering kale is unique for its vibrant colors that intensify in cool weather, providing ornamental value during the fall and winter months when many other plants are dormant. Unlike edible kale, it is primarily grown for its visual appeal rather than its flavor.
- ✓ Adds vibrant color to cool-season gardens
- ✓ Provides visual interest during the dormant season
- ✓ Attracts beneficial insects
- ✓ Easy to grow outdoors in suitable climates
- ✓ Offers a unique textural element to garden designs
- ⚠️ Toxic to pets
Perennial Flax
Perennial Flax is known for its delicate, blue flowers that open in the morning and close by afternoon. It is a relatively low-maintenance perennial that attracts pollinators and is drought-tolerant once established.
- ✓ Attracts pollinators like bees and butterflies.
- ✓ Adds a delicate, airy texture to the garden.
- ✓ Provides a long season of blue flowers.
- ✓ Drought-tolerant once established, reducing water needs.
- ✓ Relatively low-maintenance, freeing up gardening time.
- ⚠️ Toxic to pets
📅 Maintenance Schedule — Plant Care Comparison
Flowering Kale
Perennial Flax
🌞 Light Requirements
Flowering Kale
Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal color development.
Low light tolerant: ❌ No
Perennial Flax
Full sun
Low light tolerant: ❌ No
💧 Watering Needs
Flowering Kale
Water thoroughly when the top inch of soil feels dry. Avoid overwatering, which can lead to root rot. Ensure good drainage. Signs of overwatering include yellowing leaves and a soggy soil. Underwatering is indicated by wilting leaves.
Perennial Flax
Water thoroughly when the top inch of soil feels dry. Avoid overwatering, which can lead to root rot. Ensure good drainage. Signs of underwatering include wilting and yellowing leaves. Overwatering can cause root rot and fungal diseases.
🌡️ Temperature & Humidity
Flowering Kale
Temperature: 4-18°C
Humidity: 40-60%
Perennial Flax
Temperature: 15-24°C
Humidity: 30-50%
🤔 Which Plant Is Right For You?
Flowering Kale
Brassica oleracea var. acephalaGardeners looking to add vibrant color to their fall and winter gardens.
✅ Choose This Plant If...
- You want vibrant fall and winter color in your garden.
- You have a sunny outdoor space with cool temperatures.
- You enjoy container gardening with seasonal plants.
- You want a low-maintenance plant for outdoor displays.
- You appreciate the unique texture and form of ornamental foliage.
❌ Skip This Plant If...
- You have limited sunlight indoors.
- You live in a consistently warm climate.
- You have pets that might ingest the plant.
- You are looking for a long-term indoor houseplant.
Perennial Flax
Linum perenneGardeners looking for a low-maintenance, flowering perennial for sunny locations.
✅ Choose This Plant If...
- You want a low-maintenance perennial for a sunny garden.
- You want to attract pollinators to your garden.
- You appreciate delicate, blue flowers.
- You have well-draining soil.
- You live in a climate with mild winters.
❌ Skip This Plant If...
- You have pets that might ingest the plant.
- You don't have a sunny outdoor space.
- You are looking for an easy indoor plant.
🎯 Quick Verdict
⚡ Key Differences Between These Plants
Flowering Kale has moderate growth, while Perennial Flax grows moderate.
💡 Pro Tips For Comparing These Plants
Flowering Kale Care Tips
Flowering kale is primarily an outdoor plant and requires full sun and cool temperatures to thrive. It is challenging to maintain indoors due to its high light requirements and sensitivity to warm, dry air. Indoor plants often become leggy and lose their color.
- Plant in well-draining soil to prevent root rot.
- Provide at least 6 hours of direct sunlight daily for best color.
- Water regularly, but avoid overwatering.
- Fertilize every 2-4 weeks with a balanced liquid fertilizer.
- Protect from extreme cold or frost if necessary.
Perennial Flax Care Tips
Perennial Flax is primarily an outdoor plant and is challenging to grow indoors due to its high light requirements. It needs full sun and well-draining soil. Indoor attempts often result in leggy growth and poor flowering. It is toxic to pets.
- Ensure well-draining soil to prevent root rot.
- Provide full sun for optimal flowering.
- Deadhead spent flowers regularly to encourage more blooms.
- Apply a balanced fertilizer in spring.
- Protect from excessive moisture in winter.
⚠️ Common Problems & Solutions — Plant Care Comparison
Flowering Kale
Perennial Flax
❓ Frequently Asked Questions — Comparing These Plants
Flowering Kale
What are the light requirements for Flowering Kale?
Flowering Kale needs at least six hours of direct sunlight per day to develop its best color. Insufficient light can lead to leggy growth and dull coloration. When planting, choose a location that receives full sun exposure. If growing in containers, rotate the plants regularly to ensure even light exposure on all sides.
How do I care for Flowering Kale?
Flowering Kale thrives in cool temperatures (40-70°F) and requires at least 6 hours of sunlight daily. Plant in well-draining soil, enriched with compost or other organic matter. Water regularly, keeping the soil consistently moist but not waterlogged. Fertilize every 2-3 weeks with a balanced fertilizer during the growing season to promote vibrant color.
How do I propagate Flowering Kale?
Flowering Kale is primarily grown from seed, but propagation through stem cuttings is possible, though less common. Take stem cuttings from healthy, non-flowering shoots in late summer or early fall. Dip the cut end in rooting hormone and plant in a well-draining potting mix. Keep the cuttings moist and in a warm, humid environment until roots develop.
Perennial Flax
What are the light requirements for Perennial Flax?
Perennial Flax requires a minimum of six hours of direct sunlight per day to thrive and produce abundant blooms. A south-facing location is ideal, but east or west-facing exposures can also work if they provide sufficient sunlight. Insufficient light can lead to leggy growth, reduced flowering, and pale foliage. If growing indoors, place the plant near a sunny window or supplement with artificial grow lights. Rotate the plant regularly to ensure even light exposure on all sides. When transplanting, choose a location that receives full sun throughout the day. Be mindful of shadows cast by trees or buildings, especially during the shorter days of winter.
How do I care for Perennial Flax?
Perennial Flax thrives in full sun and well-drained soil. Water deeply but infrequently, allowing the soil to dry out between waterings. Amend heavy clay soils with compost or other organic matter to improve drainage. Fertilize lightly in spring with a balanced fertilizer to encourage blooming. Deadhead spent flowers to promote continued flowering. Cut back the plant after blooming to maintain its shape and encourage bushier growth. Provide support if necessary, as the stems can become leggy. Protect from excessive winter moisture in colder climates. Mulch around the base of the plant to retain moisture and suppress weeds. Monitor for pests and diseases, and treat promptly if necessary. Divide established plants every few years to rejuvenate them.
How do I propagate Perennial Flax?
Perennial Flax can be propagated by seed, division, or stem cuttings.
Last updated: May 16, 2026 — Plant care data reviewed and verified by our editorial team.