Onion vs Philodendron Selloum Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Onion
Allium cepa
The onion (Allium cepa) is a biennial plant, typically grown as an annual, cultivated for its edible bulb. It features hollow, bluish-green leaves and a bulb that develops at the base of the plant. Onions are primarily grown outdoors in gardens or fields. While it's possible to sprout an onion indoors, it's not typically grown to full maturity as a houseplant due to its strong odor and specific environmental needs. People grow onions for culinary purposes, adding flavor to a wide variety of dishes.
Philodendron Selloum
Thaumatophyllum bipinnatifidum (syn. Philodendron selloum)
Thaumatophyllum bipinnatifidum, commonly known as Selloum, is a large, evergreen plant characterized by its deeply lobed, glossy green leaves. It is often grown as an ornamental plant, both indoors and outdoors, although it thrives best in warm, humid environments. While often referred to as a Philodendron, it was reclassified into the genus Thaumatophyllum. In its natural habitat, it can grow quite large, forming a trunk-like stem. People grow it for its dramatic foliage and tropical appearance, adding a lush, architectural element to landscapes and interiors. It is primarily an outdoor plant but can adapt to indoor conditions with proper care.
Quick Plant Comparison
| Feature | Onion | Philodendron Selloum |
|---|---|---|
| Light | Full sun (6-8 hours of direct sunlight daily) | Bright, indirect light. Can tolerate some direct morning sun, but avoid intense afternoon sun. |
| Watering | Every 5-7 days, depending on weather and soil drainage | Every 1-2 weeks, depending on environmental conditions and pot size. |
| Humidity | 40-60% | 40-70% |
| Temperature | 13-24°C | 18-24°C |
| Care Level | Expert | Moderate |
| Growth Rate | Moderate | Moderate |
| Max Height | Outdoors: 30-60 cm. Indoors (sprouted): Up to 30cm | 1-1.5 meters indoors |
| Pet Safety | ❌ Toxic To Pets | ❌ Toxic To Pets |
| Soil | Well-draining, fertile soil rich in organic matter | Well-draining potting mix, such as a mix of peat moss, perlite, and pine bark. |
| Beginner Friendly | With Caution | With Caution |
| Weekly Maintenance | 30 minutes weekly (weeding, watering, pest control) | 15 minutes weekly |
🔬 Botanical Information — Comparing These Plants
Onion
| Scientific Name | Allium cepa |
|---|---|
| Family | Amaryllidaceae |
| Native To | Central Asia |
| Also Known As | Onion, Bulb Onion, Common Onion |
| Leaves | The leaves are hollow, cylindrical, and bluish-green, growing directly from the bulb. They are typically 30-50 cm long and taper to a point. |
| Flowers | Onions produce a spherical umbel of small, white or purple flowers on a tall stalk. Flowering is more common in the second year of growth. Flowering rarely occurs indoors. |
Philodendron Selloum
| Scientific Name | Thaumatophyllum bipinnatifidum (syn. Philodendron selloum) |
|---|---|
| Family | Araceae |
| Native To | South America, specifically Brazil, Paraguay, Bolivia, and Argentina |
| Also Known As | Split-leaf Philodendron, Selloum, Horsehead Philodendron, Lacy Tree Philodendron |
| Leaves | The leaves are large, deeply lobed, and glossy green. They can grow up to 90 cm long and 60 cm wide. The lobes are irregular and give the leaves a distinctive, feathery appearance. New leaves emerge a lighter green and gradually darken with age. |
| Flowers | It rarely flowers indoors. When it does flower, it produces a spadix and spathe, typical of plants in the Araceae family. The flowers are not particularly showy. |
📏 Size & Growth — Plant Comparison
Onion
Philodendron Selloum
🌱 Propagation — Comparing Plant Growth
Onion
Methods: Seed, Bulb division
Difficulty: Easy
Tips: Start seeds indoors 8-10 weeks before the last frost or plant sets (small bulbs) directly in the garden after the last frost. For bulb division, separate small bulbs from a larger cluster and plant them individually.
Philodendron Selloum
Methods: Stem cuttings, Division, Seed (rarely used)
Difficulty: Moderate
Tips: Take stem cuttings with aerial roots. Allow the cut end to callous over for a day or two before planting in moist potting mix. Keep the cutting warm and humid.
✨ Benefits & Features — Comparing Plant Value
Onion
The onion is a bulbous plant with a distinctive pungent odor and flavor. Its layers of fleshy scales form the edible bulb, which is used in a wide variety of culinary applications.
- ✓ Provides fresh, flavorful onions for cooking.
- ✓ Rich in vitamins and minerals.
- ✓ Can deter pests in the garden.
- ✓ Offers a rewarding gardening experience.
- ✓ Supports sustainable food practices.
- ⚠️ Toxic to pets
Philodendron Selloum
Its deeply lobed leaves give it a unique and dramatic appearance. It's also relatively easy to propagate from stem cuttings. The plant's size and architectural form make it a standout feature in any space.
- ✓ Adds a tropical aesthetic to your space.
- ✓ Can improve indoor air quality.
- ✓ Provides a sense of calm and connection to nature.
- ✓ Its large leaves create a visually striking focal point.
- ✓ Relatively low-maintenance once established.
- 🌬️ NASA-verified air purifier
- ⚠️ Toxic to pets
📅 Maintenance Schedule — Plant Care Comparison
Onion
Philodendron Selloum
🌞 Light Requirements
Onion
Full sun (6-8 hours of direct sunlight daily)
Low light tolerant: ❌ No
Philodendron Selloum
Bright, indirect light. Can tolerate some direct morning sun, but avoid intense afternoon sun.
Low light tolerant: ✅ Yes
💧 Watering Needs
Onion
Water deeply when the top inch of soil is dry. Avoid overwatering, which can lead to bulb rot. Signs of overwatering include yellowing leaves and a soft, mushy bulb. Underwatering is indicated by wilting leaves and stunted growth.
Philodendron Selloum
Water thoroughly when the top 2-3 inches of soil are dry. Allow excess water to drain away. Overwatering can lead to root rot, indicated by yellowing leaves and a musty smell. Underwatering results in drooping leaves and dry, crispy edges.
🌡️ Temperature & Humidity
Onion
Temperature: 13-24°C
Humidity: 40-60%
Philodendron Selloum
Temperature: 18-24°C
Humidity: 40-70%
🤔 Which Plant Is Right For You?
Onion
Allium cepaGardeners looking to grow their own culinary onions.
✅ Choose This Plant If...
- You want to grow your own fresh onions for cooking.
- You have a sunny outdoor garden space.
- You enjoy the process of nurturing plants from seed to harvest.
- You want to control the quality and source of your food.
- You are looking for a companion plant to deter pests in your vegetable garden.
❌ Skip This Plant If...
- You have pets that might ingest the plant.
- You lack a sunny outdoor space.
- You are sensitive to strong odors.
Philodendron Selloum
Thaumatophyllum bipinnatifidum (syn. Philodendron selloum)Experienced plant enthusiasts who can provide ample space and attention to its specific needs.
✅ Choose This Plant If...
- You want a bold, tropical statement plant.
- You have a bright, indirect light location.
- You are experienced with plant care and can manage its needs.
- You appreciate its architectural foliage.
- You are prepared to provide ample space for its growth.
❌ Skip This Plant If...
- You have pets that might ingest the plant.
- You have limited space.
- You tend to overwater your plants.
🎯 Quick Verdict
⚡ Key Differences Between These Plants
Onion is rated Expert care level, while Philodendron Selloum is Moderate.
💡 Pro Tips For Comparing These Plants
Onion Care Tips
Onions are primarily outdoor plants requiring full sun and well-drained soil. Growing them indoors is challenging due to their need for intense sunlight and the potential for strong odors. While sprouting an onion indoors is possible, achieving a mature bulb is difficult.
- Plant in well-drained soil amended with compost.
- Water deeply but infrequently, allowing the soil to dry slightly between waterings.
- Fertilize regularly during the growing season with a balanced fertilizer.
- Protect from pests and diseases with appropriate measures.
- Harvest when the tops begin to fall over and the bulbs are mature.
Philodendron Selloum Care Tips
While adaptable to indoor conditions, Selloum prefers bright, indirect light and well-draining soil. Maintaining adequate humidity and avoiding overwatering are crucial for its health. It can become quite large, requiring ample space. Regular cleaning of the leaves will keep it looking its best.
- Wipe the leaves regularly with a damp cloth to remove dust and improve photosynthesis.
- Provide a moss pole or other support for the plant to climb, mimicking its natural growth habit.
- Rotate the plant regularly to ensure even growth on all sides.
- Avoid placing the plant near drafts or heating vents.
- Monitor for pests regularly and treat promptly.
⚠️ Common Problems & Solutions — Plant Care Comparison
Onion
Philodendron Selloum
❓ Frequently Asked Questions — Comparing These Plants
Onion
What are the light requirements for Onion?
Flowering onions require ample sunlight to thrive and produce abundant blooms. Aim for at least 6-8 hours of direct sunlight per day. Inadequate light can lead to leggy growth, weak stems, and reduced flowering. If growing indoors, place your onion plant near a south-facing window where it can receive maximum sunlight exposure. If natural light is insufficient, supplement with grow lights. Rotate the plant regularly to ensure even light distribution and prevent it from leaning towards the light source. Monitor the foliage for signs of sunburn, which can occur if the plant is exposed to intense afternoon sun. Adjust the placement or provide shade if necessary.
How do I care for Onion?
Flowering onions thrive with proper care. Plant bulbs in well-draining soil in a sunny location. Water thoroughly after planting and then moderately, allowing the soil to dry slightly between waterings. Fertilize sparingly with a balanced fertilizer during the growing season, and increase phosphorus before blooming. Deadhead spent flowers to encourage continued blooming. Provide support for taller varieties to prevent drooping. In colder climates, protect bulbs with a layer of mulch during winter. Monitor for pests and diseases, and address promptly. Ensure good air circulation to prevent fungal issues. Repot container-grown onions every few years to refresh the soil. Regular check-ups will keep your onion plant healthy and flourishing.
How do I propagate Onion?
Flowering onions can be propagated through several methods. Division is the most common and easiest. When the plant is dormant, carefully dig up the clump and separate the bulbs. Replant the individual bulbs in well-draining soil. Stem cuttings are not typically used for onion propagation. Keiki (small plantlets that form on the flower stalk) are rare in onions. For bulb offsets, detach them carefully from the mother bulb and plant them separately. Water regularly and provide adequate sunlight. Propagation is best done in the fall or early spring. Ensure the new plants have adequate space to develop their root systems. With proper care, the propagated onions will develop into mature, flowering plants within a year or two.
Philodendron Selloum
What are the light requirements for Philodendron Selloum?
Philodendron Selloum flourishes in bright, indirect light. Avoid direct sunlight, especially during the hottest part of the day, as it can cause leaf burn. An east-facing window is ideal, or a spot near a south or west-facing window that is filtered by a sheer curtain. If the plant is not receiving enough light, the leaves may become pale or the stems may become leggy. Rotate the plant regularly to ensure even growth on all sides. Artificial grow lights can be used to supplement natural light, especially during winter months.
How do I care for Philodendron Selloum?
Philodendron Selloum thrives in bright, indirect light, avoiding direct sunlight which can scorch its leaves. Water thoroughly when the top inch of soil feels dry, allowing excess water to drain. Use a well-draining potting mix to prevent root rot. Maintain humidity levels around 60-70% through misting or a humidifier. Fertilize monthly during the growing season (spring and summer) with a balanced liquid fertilizer. Prune any yellow or damaged leaves to encourage healthy growth. Repot every 1-2 years as needed, when the plant becomes root-bound. Provide support for mature plants as they grow larger. Protect from drafts and sudden temperature changes.
How do I propagate Philodendron Selloum?
Philodendron Selloum can be propagated through stem cuttings, division, or air layering. For stem cuttings, take a cutting with at least one node and place it in water or moist soil. For division, carefully separate the plant into multiple sections, ensuring each section has roots. For air layering, make a small cut on the stem, wrap it in moist sphagnum moss, and cover it with plastic wrap until roots develop. Plant the rooted cutting or division in well-draining soil. Maintain high humidity during propagation.
Last updated: May 7, 2026 — Plant care data reviewed and verified by our editorial team.