Lobelia vs Natal Plum Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Lobelia
Lobelia cardinalis
Lobelia cardinalis, the cardinal flower, is a herbaceous perennial native to North America. It typically grows to a height of 2-4 feet. It features vibrant red, tubular flowers arranged on upright spikes. This plant is primarily grown outdoors in moist, well-drained soil, often near streams or ponds. While its striking color makes it desirable, it's challenging to maintain indoors due to its high light and humidity requirements. Gardeners cultivate it for its beauty and its attraction to hummingbirds and butterflies.
Natal Plum
Carissa macrocarpa
Carissa macrocarpa, or Natal Plum, is a dense, evergreen shrub or small tree known for its glossy, dark green leaves and fragrant, star-shaped white flowers. It produces edible, plum-like red fruits that are rich in vitamin C. While it can be grown in containers, it's primarily an outdoor plant, thriving in warm climates. People grow it for its ornamental value, edible fruit, and use as a security hedge due to its thorny branches. It's not ideally suited as an indoor plant due to high light requirements and potential size.
Quick Plant Comparison
| Feature | Lobelia | Natal Plum |
|---|---|---|
| Light | Full sun to partial shade | Full sun to partial shade. Requires at least 6 hours of direct sunlight daily to thrive and produce fruit. |
| Watering | Every 2-3 days, depending on weather and soil drainage | Every 7-14 days, depending on environmental conditions and pot size. |
| Humidity | 60-80% | 40-60% |
| Temperature | 15-25°C | 18-27°C |
| Care Level | Expert | Expert |
| Growth Rate | Moderate | Moderate |
| Max Height | N/A (Primarily outdoor plant) | Indoors: Rarely exceeds 1-2 meters. Outdoors: Up to 4 meters. |
| Pet Safety | ❌ Toxic To Pets | ❌ Toxic To Pets |
| Soil | Rich, well-drained, consistently moist soil | Well-draining soil mix, such as a combination of potting soil, perlite, and sand. |
| Beginner Friendly | ❌ No | ❌ No |
| Weekly Maintenance | 15 minutes weekly | 30 minutes weekly (including watering, pruning, and pest control) |
🔬 Botanical Information — Comparing These Plants
Lobelia
| Scientific Name | Lobelia cardinalis |
|---|---|
| Family | Campanulaceae |
| Native To | North America |
| Also Known As | Cardinal flower, Red lobelia |
| Leaves | The leaves are lance-shaped, toothed, and arranged alternately along the stem. They are typically a medium green color. |
| Flowers | It rarely flowers indoors. Outdoors, it produces vibrant red, tubular flowers arranged on upright spikes. The flowers bloom from mid-summer to early fall. |
Natal Plum
| Scientific Name | Carissa macrocarpa |
|---|---|
| Family | Apocynaceae |
| Native To | South Africa |
| Also Known As | Natal Plum, Large Num-Num |
| Leaves | The leaves are glossy, dark green, and oval-shaped, measuring 2-5 cm in length. They are arranged oppositely on the stems and have a leathery texture. |
| Flowers | Natal Plum produces fragrant, star-shaped white flowers in spring and summer. While it can flower indoors with sufficient light, fruit production is less common. |
📏 Size & Growth — Plant Comparison
Lobelia
Natal Plum
🌱 Propagation — Comparing Plant Growth
Lobelia
Methods: Seed, Division, Stem cuttings
Difficulty: Moderate
Tips: For seeds, cold stratify for a few weeks before sowing. Division is best done in spring or fall. Stem cuttings should be taken in spring and rooted in water or moist soil.
Natal Plum
Methods: Stem cuttings, Seed
Difficulty: Moderate
Tips: Take semi-hardwood cuttings in spring or summer. Dip the cut end in rooting hormone and plant in a well-draining potting mix. Keep the soil moist and provide warmth and humidity.
✨ Benefits & Features — Comparing Plant Value
Lobelia
The vibrant red color and tubular shape of the flowers are specifically adapted to attract hummingbirds. It is a native North American plant, making it a valuable addition to local ecosystems.
- ✓ Attracts pollinators like hummingbirds and butterflies
- ✓ Adds vibrant color to the garden
- ✓ Provides a natural habitat for wildlife
- ✓ Contributes to biodiversity
- ✓ Offers a visually appealing focal point
- ⚠️ Toxic to pets
Natal Plum
The Natal Plum is unique for its combination of fragrant flowers, edible fruit, and thorny branches. Its drought tolerance makes it a suitable choice for xeriscaping.
- ✓ Provides edible fruit rich in Vitamin C
- ✓ Offers fragrant flowers that attract pollinators
- ✓ Acts as a natural security barrier due to its thorns
- ✓ Adds an ornamental touch to gardens with its glossy foliage
- ✓ Can be used in traditional medicine (with caution and expert knowledge)
- ⚠️ Toxic to pets
📅 Maintenance Schedule — Plant Care Comparison
Lobelia
Natal Plum
🌞 Light Requirements
Lobelia
Full sun to partial shade
Low light tolerant: ❌ No
Natal Plum
Full sun to partial shade. Requires at least 6 hours of direct sunlight daily to thrive and produce fruit.
Low light tolerant: ❌ No
💧 Watering Needs
Lobelia
Keep soil consistently moist, especially during hot weather. Overwatering can lead to root rot, indicated by yellowing leaves and a foul smell. Underwatering results in wilting and dry, crispy leaves.
Natal Plum
Water deeply when the top inch of soil is dry. Avoid overwatering, which can lead to root rot. Allow the soil to dry slightly between waterings. Signs of underwatering include wilting leaves; overwatering includes yellowing leaves and soggy soil.
🌡️ Temperature & Humidity
Lobelia
Temperature: 15-25°C
Humidity: 60-80%
Natal Plum
Temperature: 18-27°C
Humidity: 40-60%
🤔 Which Plant Is Right For You?
Lobelia
Lobelia cardinalisExperienced gardeners looking to attract hummingbirds to their outdoor garden.
✅ Choose This Plant If...
- You want to attract hummingbirds to your garden.
- You have a consistently moist area in your garden.
- You appreciate vibrant red flowers.
- You are an experienced gardener looking for a rewarding challenge.
- You want a native North American plant.
❌ Skip This Plant If...
- You have pets that may ingest the plant.
- You have a dry garden.
- You are a beginner gardener.
- You want a low-maintenance plant.
Natal Plum
Carissa macrocarpaExperienced gardeners in warm climates who want an ornamental shrub with edible fruit, and who can ensure it is kept away from pets.
✅ Choose This Plant If...
- You live in a warm climate with plenty of sunshine.
- You want an ornamental shrub with fragrant flowers and edible fruit.
- You need a natural barrier or security hedge.
- You are an experienced gardener looking for a new challenge.
- You are willing to provide the specific care this plant needs.
❌ Skip This Plant If...
- You have pets or small children due to the plant's toxicity.
- You live in a cold climate with limited sunlight.
- You are a beginner gardener.
- You don't have space for a large shrub.
- You are looking for a low-maintenance indoor plant.
🎯 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 Care Tips
Lobelia cardinalis is primarily an outdoor plant and is very difficult to grow indoors. It requires high light, consistent moisture, and high humidity, which are challenging to replicate in a typical indoor environment. It is prone to root rot if not properly drained.
- Provide consistent moisture, especially during hot weather.
- Deadhead spent flowers to encourage more blooms.
- Protect from frost in winter with mulch.
- Monitor for pests and diseases regularly.
- Plant in a location with good air circulation to prevent powdery mildew.
Natal Plum Care Tips
Natal Plum is primarily an outdoor plant and requires significant sunlight to thrive. Growing it indoors is challenging due to its high light needs and potential size. It needs well-draining soil, moderate watering, and occasional fertilization. Toxicity to pets is a major concern.
- Provide at least 6 hours of direct sunlight daily for optimal growth and fruit production.
- Water deeply but infrequently, allowing the soil to dry slightly between waterings.
- Fertilize regularly during the growing season with a balanced fertilizer.
- Prune regularly to maintain shape and encourage new growth.
- Protect from frost in colder climates.
⚠️ Common Problems & Solutions — Plant Care Comparison
Lobelia
Natal Plum
❓ Frequently Asked Questions — Comparing These Plants
Lobelia
What are the light requirements for Lobelia?
Lobelia flourishes in bright, indirect light. Direct sunlight, especially during the hottest part of the day, can scorch its delicate foliage. An east-facing window is often ideal, providing gentle morning sun. If growing outdoors, choose a location that receives partial shade, particularly during the afternoon. Insufficient light can result in leggy growth and reduced blooming. Observe your plant closely and adjust its location as needed to ensure it receives the appropriate amount of light. Rotate container-grown Lobelia periodically to ensure even light exposure on all sides. Supplement natural light with grow lights if necessary, especially during the winter months.
How do I care for Lobelia?
Lobelia thrives with consistent care. Provide bright, indirect light to encourage abundant blooming. Water regularly, keeping the soil consistently moist but not waterlogged; allow the top inch of soil to dry slightly between waterings. Fertilize every 2-4 weeks during the growing season with a balanced liquid fertilizer diluted to half strength to promote flowering. Pinch back stems regularly to encourage bushier growth and more blooms. Maintain a temperature range of 60-75°F (15-24°C) and provide adequate humidity, especially indoors. Deadhead spent flowers to prolong the blooming period. Repot annually in spring if needed, using a well-draining potting mix. Monitor for pests like aphids and spider mites, and treat promptly if detected. Ensure good air circulation to prevent fungal diseases.
How do I propagate Lobelia?
Lobelia can be propagated through stem cuttings or division.
Natal Plum
What are the light requirements for Natal Plum?
Natal Plum requires ample sunlight to flourish and produce its characteristic blooms and fruits. Ideally, it should receive at least 6 hours of direct sunlight per day. In regions with intense sunlight, particularly during the hottest part of the day, providing some afternoon shade can prevent leaf scorch.
How do I care for Natal Plum?
Natal Plum thrives in full sun to partial shade. Ensure at least 6 hours of sunlight daily for optimal flowering and fruit production. Water thoroughly when the top inch of soil feels dry, allowing excess water to drain. Avoid overwatering, which can lead to root rot. Maintain moderate humidity, especially indoors.
How do I propagate Natal Plum?
Natal Plum can be propagated through stem cuttings. Take 4-6 inch stem cuttings from healthy, non-flowering shoots in spring or summer. Remove the lower leaves and dip the cut end in rooting hormone. Plant the cuttings in a well-draining potting mix. Keep the soil moist and provide bright, indirect light. Rooting typically occurs within 4-8 weeks.
Last updated: April 29, 2026 — Plant care data reviewed and verified by our editorial team.