Empress Tree vs Kohlrabi Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Empress Tree
Paulownia tomentosa
The Empress Tree is a fast-growing deciduous tree known for its large, heart-shaped leaves and fragrant, showy purple flowers that bloom in early spring before the leaves emerge. It is primarily an outdoor tree, reaching heights of 30-60 feet. People grow it for its ornamental value, providing shade and adding a striking visual element to landscapes. While it can be grown in containers, its rapid growth and large size make it challenging to maintain indoors long-term. It is considered invasive in some regions due to its prolific seed production and ability to colonize disturbed areas.
Kohlrabi
Brassica oleracea var. gongylodes
Kohlrabi is a biennial vegetable cultivated as an annual, known for its swollen, globular stem that grows above ground. It features a crisp, mild flavor similar to a turnip or cabbage. The plant has long-stalked leaves emerging from the bulbous stem. It is primarily grown outdoors in gardens and farms for its edible stem and leaves. While it can be started indoors, it requires full sun and ample space to thrive, making it challenging to grow to maturity indoors. People grow kohlrabi for its unique texture and flavor in salads, stir-fries, and other culinary applications.
Quick Plant Comparison
| Feature | Empress Tree | Kohlrabi |
|---|---|---|
| Light | Full sun (at least 6 hours of direct sunlight daily) | Full sun (at least 6 hours of direct sunlight daily) |
| Watering | Every 1-2 weeks, depending on weather and soil drainage | Every 2-3 days outdoors, depending on weather conditions |
| Humidity | 30-50% | 40-60% |
| Temperature | 15-27°C | 15-24°C |
| Care Level | Expert | Expert |
| Growth Rate | Fast | Moderate |
| Max Height | Difficult to maintain indoors. Outdoors: 9-18 meters (30-60 feet) | 30-45 cm (outdoors) |
| Pet Safety | ❌ Toxic To Pets | ✅ Safe |
| Soil | Well-draining soil, such as a mix of loam, sand, and compost | Well-draining, fertile soil rich in organic matter |
| Beginner Friendly | ❌ No | ❌ No |
| Weekly Maintenance | 30 minutes weekly (watering, pruning, monitoring for pests) | 15-30 minutes weekly |
🔬 Botanical Information — Comparing These Plants
Empress Tree
| Scientific Name | Paulownia tomentosa |
|---|---|
| Family | Paulowniaceae |
| Native To | Central and Western China |
| Also Known As | Empress Tree, Princess Tree, Foxglove Tree |
| Leaves | The leaves are very large, heart-shaped (cordate), and typically 15-40 cm (6-16 inches) wide. They are a medium green color and have a slightly fuzzy texture when young. |
| Flowers | The Empress Tree produces large, showy panicles of fragrant, pale purple flowers in early spring, before the leaves emerge. Flowering is rare indoors. |
Kohlrabi
| Scientific Name | Brassica oleracea var. gongylodes |
|---|---|
| Family | Brassicaceae |
| Native To | Northern Europe |
| Also Known As | German turnip, turnip cabbage |
| Leaves | The leaves of kohlrabi are typically bluish-green, broad, and have a slightly waxy texture. They are attached to the stem by long, slender stalks. The leaf shape can vary, but they are generally oval or rounded with slightly serrated edges. |
| Flowers | Kohlrabi will flower in its second year if allowed to overwinter. The flowers are typical of the Brassica family, with four petals arranged in a cross shape, usually yellow or white. Flowering is rare when grown as an annual for its bulb. |
📏 Size & Growth — Plant Comparison
Empress Tree
Kohlrabi
🌱 Propagation — Comparing Plant Growth
Empress Tree
Methods: Seeds, root cuttings
Difficulty: Moderate
Tips: For seeds, stratify them in the refrigerator for a few weeks before sowing. Root cuttings should be taken in late winter or early spring.
Kohlrabi
Methods: Seed
Difficulty: Easy
Tips: Start seeds indoors 4-6 weeks before the last frost or direct sow outdoors after the last frost. Keep soil consistently moist.
✨ Benefits & Features — Comparing Plant Value
Empress Tree
The Empress Tree is distinguished by its exceptionally large leaves and early spring blooms, which appear before the leaves emerge. Its rapid growth rate also sets it apart from many other ornamental trees.
- ✓ Provides shade in the summer
- ✓ Offers beautiful spring blooms
- ✓ Attracts pollinators to the garden
- ✓ Adds a unique architectural element to the landscape
- ✓ Fast growth provides quick results.
- ⚠️ Toxic to pets
Kohlrabi
Kohlrabi is unique due to its edible, swollen stem that grows above ground, unlike root vegetables. Its mild flavor and crisp texture make it a versatile ingredient in various dishes. The plant also offers edible leaves, adding to its appeal.
- ✓ Provides fresh, nutritious vegetables
- ✓ Adds visual interest to the garden
- ✓ Encourages healthy eating habits
- ✓ Offers a unique culinary ingredient
- ✓ Supports sustainable living
- 🐾 Pet Safe
📅 Maintenance Schedule — Plant Care Comparison
Empress Tree
Kohlrabi
🌞 Light Requirements
Empress Tree
Full sun (at least 6 hours of direct sunlight daily)
Low light tolerant: ❌ No
Kohlrabi
Full sun (at least 6 hours of direct sunlight daily)
Low light tolerant: ❌ No
💧 Watering Needs
Empress Tree
Water deeply when the top few inches of soil are dry, especially during the growing season. Avoid overwatering, which can lead to root rot. In containers, ensure proper drainage. Reduce watering in the winter when the tree is dormant. Signs of underwatering include wilting leaves; overwatering includes yellowing leaves and soggy soil.
Kohlrabi
Water deeply when the top inch of soil feels dry. Avoid overwatering, which can lead to rot. Consistent moisture is important for bulb development. Signs of underwatering include wilting leaves and stunted growth. Overwatering can cause yellowing leaves and a mushy stem.
🌡️ Temperature & Humidity
Empress Tree
Temperature: 15-27°C
Humidity: 30-50%
Kohlrabi
Temperature: 15-24°C
Humidity: 40-60%
🤔 Which Plant Is Right For You?
Empress Tree
Paulownia tomentosaGardeners with large outdoor spaces who appreciate fast-growing shade trees with showy flowers.
✅ Choose This Plant If...
- You want a fast-growing shade tree
- You appreciate fragrant, showy purple flowers in early spring
- You have a large outdoor space to accommodate its size
- You want a tree that attracts pollinators
- You are willing to manage its potential for invasive spread.
❌ Skip This Plant If...
- You have a small garden or limited space
- You are looking for an easy-to-care-for indoor plant
- You live in an area where it is considered invasive
Kohlrabi
Brassica oleracea var. gongylodesGardeners looking for a unique and nutritious vegetable to grow outdoors.
✅ Choose This Plant If...
- You have a sunny garden space.
- You enjoy growing your own vegetables.
- You want a unique and nutritious addition to your diet.
- You are looking for a relatively fast-growing crop.
- You enjoy the taste of cabbage and turnips.
❌ Skip This Plant If...
- You lack sufficient outdoor space.
- You cannot provide at least 6 hours of direct sunlight daily.
- You are looking for a low-maintenance indoor plant.
🎯 Quick Verdict
⚡ Key Differences Between These Plants
Empress Tree has fast growth, while Kohlrabi grows moderate.
💡 Pro Tips For Comparing These Plants
Empress Tree Care Tips
The Empress Tree is primarily an outdoor tree that requires full sun and well-draining soil. Growing it indoors is extremely challenging due to its size and light requirements. It is best suited for outdoor landscapes where it has ample space to grow. Requires regular pruning to maintain shape and control size.
- Plant in well-draining soil to prevent root rot.
- Water deeply but infrequently, allowing the soil to dry out between waterings.
- Prune regularly to maintain shape and control size.
- Fertilize in early spring with a balanced fertilizer.
- Monitor for pests and diseases and treat promptly.
Kohlrabi Care Tips
Kohlrabi is primarily an outdoor plant that requires full sun and consistent moisture. Growing it indoors is challenging due to the high light requirements and space needed for bulb development. It's best suited for experienced gardeners with outdoor space.
- Start seeds indoors for an earlier harvest.
- Ensure well-draining soil to prevent rot.
- Provide consistent moisture for optimal bulb development.
- Fertilize regularly during the growing season.
- Protect from pests like aphids and cabbage worms.
⚠️ Common Problems & Solutions — Plant Care Comparison
Empress Tree
Kohlrabi
❓ Frequently Asked Questions — Comparing These Plants
Empress Tree
What are the light requirements for Empress Tree?
Empress Trees need bright, indirect light to thrive indoors. Insufficient light will result in leggy growth and smaller leaves. An east-facing window is ideal, providing gentle morning sun. A south-facing window can also work, but shield the plant from intense midday sun with a sheer curtain. Rotate the plant regularly to ensure even light exposure on all sides. If natural light is insufficient, supplement with a grow light. Place the grow light 12-18 inches away from the plant. Observe the plant’s response to the light and adjust accordingly. A lack of light causes stunted growth and pale foliage.
How do I care for Empress Tree?
Empress Tree requires bright, indirect light; too much direct sun can scorch the leaves. Water thoroughly when the top inch of soil is dry, ensuring good drainage to prevent root rot. A well-draining potting mix is crucial. Maintain a temperature between 65-75°F (18-24°C). Humidity levels should be moderate to high; consider using a humidifier or pebble tray. Fertilize monthly during the growing season (spring and summer) with a balanced liquid fertilizer diluted to half strength. Prune regularly to maintain shape and encourage bushier growth; remove any dead or yellowing leaves. Repot annually in spring, increasing pot size as needed. Monitor for pests like spider mites and aphids, and treat promptly with insecticidal soap. Providing stable conditions are key to health and growth.
How do I propagate Empress Tree?
Empress Tree can be propagated through stem cuttings or air layering. For stem cuttings, take a 4-6 inch cutting from a healthy stem in spring. Remove the lower leaves and dip the cut end in rooting hormone. Plant the cutting in a well-draining potting mix and keep it moist. Cover with a plastic bag to increase humidity. Roots should develop in 4-6 weeks. For air layering, make a shallow cut on a stem and wrap it with moist sphagnum moss. Cover the moss with plastic wrap and secure it with tape. Keep the moss moist. Roots should develop in several weeks. Once roots are visible, cut the stem below the roots and plant it in a pot. Ensure stable conditions during propagation.
Kohlrabi
What are the light requirements for Kohlrabi?
Kohlrabi thrives in full sun, requiring at least 6 hours of direct sunlight per day to produce healthy bulbs. Insufficient light can lead to leggy growth and smaller, less flavorful bulbs. In hotter climates, providing some afternoon shade can prevent the plant from bolting (prematurely going to seed). When growing indoors, place Kohlrabi near a south-facing window or use grow lights to supplement natural light. Rotate the plants regularly to ensure even light exposure on all sides. Monitor the leaves for signs of insufficient light, such as pale color or elongated stems, and adjust the light accordingly.
How do I care for Kohlrabi?
Kohlrabi requires well-draining soil rich in organic matter. Plant seeds directly in the garden or start indoors 4-6 weeks before the last frost. Space plants 6-8 inches apart in rows 12-18 inches apart. Water regularly, keeping the soil consistently moist but not waterlogged. Fertilize every 2-3 weeks with a balanced fertilizer, paying attention to potassium levels to promote strong bulb development. Kohlrabi prefers full sun but can tolerate partial shade, especially in warmer climates. Harvest when the bulb reaches 2-3 inches in diameter for the best flavor and texture. Protect from pests like cabbage worms and aphids with appropriate organic pest control methods. Rotate crops annually to prevent soilborne diseases.
How do I propagate Kohlrabi?
Kohlrabi is typically propagated by seed, but it is possible to propagate it through vegetative methods, although less common.
Last updated: April 21, 2026 — Plant care data reviewed and verified by our editorial team.