Mexican Petunia vs Monkey Grass Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
Mexican Petunia
Ruellia simplex
Mexican Petunia is a fast-growing, herbaceous perennial often grown for its showy, trumpet-shaped flowers that come in shades of purple, pink, and white. It typically reaches a height of 1-3 feet. While visually appealing, it's considered invasive in many regions due to its aggressive spreading nature via rhizomes and seeds. It is primarily an outdoor plant, thriving in warm climates. People grow it for its vibrant flowers and relatively low maintenance in suitable outdoor environments. Indoor cultivation is challenging due to its high light requirements and aggressive growth.
Monkey Grass
Liriope muscari
Liriope muscari, commonly known as lilyturf or monkey grass, is a grass-like perennial often used as a ground cover or border plant. It features clumps of arching, strap-like, dark green leaves. While it resembles grass, it's not a true grass. It produces spikes of small, lavender to purple flowers in late summer, followed by blackish berries. Primarily an outdoor plant, it's valued for its low maintenance, drought tolerance, and ability to suppress weeds. It's rarely grown indoors due to its need for bright light and outdoor conditions.
Quick Plant Comparison
| Feature | Mexican Petunia | Monkey Grass |
|---|---|---|
| Light | Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal flowering. | Full sun to partial shade outdoors. Requires very bright, direct light if attempted indoors. |
| Watering | Every 3-7 days during the growing season, less frequently in winter. | Outdoors: Every 7-14 days, depending on rainfall and temperature. Indoors (if attempted): Every 7-10 days, allowing the soil to dry slightly between waterings. |
| Humidity | 30-50% | 40-60% |
| Temperature | 18-27°C | 15-27°C |
| Care Level | Expert | Expert |
| Growth Rate | Fast | Moderate; Can Spread Via Rhizomes. |
| Max Height | 0.3-0.9 meters (indoors, likely smaller than outdoors) | Outdoors: 30-45 cm. Indoors (unlikely to thrive): 20-30cm |
| Pet Safety | ❌ Toxic To Pets | ❌ Toxic To Pets |
| Soil | Well-draining soil, such as a mix of potting soil, perlite, and sand. | Well-draining soil; sandy loam is ideal. Avoid heavy clay soils. |
| Beginner Friendly | ❌ No | ❌ No |
| Weekly Maintenance | 30 minutes weekly (primarily for pruning and controlling spread). | 10 minutes weekly (mostly weeding around the plant) |
🔬 Botanical Information — Comparing These Plants
Mexican Petunia
| Scientific Name | Ruellia simplex |
|---|---|
| Family | Acanthaceae |
| Native To | Mexico, South America, and the West Indies |
| Also Known As | Mexican Petunia, Ruellia, Britton's Wild Petunia, Mexican Bluebell |
| Leaves | The leaves are lance-shaped, dark green, and have a slightly serrated edge. They are typically 10-15 cm long and arranged oppositely along the stem. |
| Flowers | It rarely flowers indoors. Outdoors, it produces trumpet-shaped flowers that are typically purple, but can also be pink or white. The flowers bloom throughout the warm months, attracting pollinators. |
Monkey Grass
| Scientific Name | Liriope muscari |
|---|---|
| Family | Asparagaceae |
| Native To | East Asia (China, Japan, Korea) |
| Also Known As | Lilyturf, Border Grass |
| Leaves | Strap-like, linear leaves, typically dark green in color. Can be variegated in some cultivars. Leaves are typically 20-40 cm long and 1-2 cm wide. |
| Flowers | Produces spikes of small, lavender to purple flowers in late summer. Flowering is rare and less pronounced when grown indoors. |
📏 Size & Growth — Plant Comparison
Mexican Petunia
Monkey Grass
🌱 Propagation — Comparing Plant Growth
Mexican Petunia
Methods: Stem cuttings, Division, Seed
Difficulty: Easy
Tips: Stem cuttings root easily in water or directly in soil. Division is best done in spring or fall. Seeds can be sown directly into the ground or started indoors.
Monkey Grass
Methods: Division, Seed
Difficulty: Easy
Tips: Division is best done in spring or fall. Dig up a clump and separate the rhizomes, ensuring each division has roots and leaves. Plant the divisions in well-draining soil.
✨ Benefits & Features — Comparing Plant Value
Mexican Petunia
Mexican Petunia is known for its ability to thrive in hot, humid conditions and its tolerance of drought once established. Its aggressive spreading habit distinguishes it from many other flowering perennials.
- ✓ Attracts pollinators like butterflies and hummingbirds.
- ✓ Adds vibrant color to the garden.
- ✓ Relatively drought-tolerant once established.
- ✓ Provides a long blooming season.
- ✓ Can be used as a ground cover (with careful management).
- ⚠️ Toxic to pets
Monkey Grass
It is a grass-like perennial that is not a true grass. It produces attractive flower spikes and berries. It is drought-tolerant and relatively low-maintenance once established.
- ✓ Erosion control on slopes.
- ✓ Low maintenance ground cover.
- ✓ Weed suppression in garden beds.
- ✓ Drought tolerance once established.
- ✓ Provides visual interest with its foliage and flowers.
- ⚠️ Toxic to pets
📅 Maintenance Schedule — Plant Care Comparison
Mexican Petunia
Monkey Grass
🌞 Light Requirements
Mexican Petunia
Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal flowering.
Low light tolerant: ❌ No
Monkey Grass
Full sun to partial shade outdoors. Requires very bright, direct light if attempted indoors.
Low light tolerant: ❌ No
💧 Watering Needs
Mexican Petunia
Water thoroughly when the top inch of soil feels dry. Avoid overwatering, which can lead to root rot. During the growing season, water more frequently. Reduce watering in the winter. Signs of underwatering include wilting leaves; overwatering includes yellowing leaves and soggy soil.
Monkey Grass
Water thoroughly when the top inch of soil is dry. Overwatering can lead to root rot, especially in poorly draining soil. Underwatering will cause the leaves to brown and droop. Ensure good drainage.
🌡️ Temperature & Humidity
Mexican Petunia
Temperature: 18-27°C
Humidity: 30-50%
Monkey Grass
Temperature: 15-27°C
Humidity: 40-60%
🤔 Which Plant Is Right For You?
Mexican Petunia
Ruellia simplexExperienced gardeners in warm climates who want a vibrant, flowering plant for their outdoor space, and are prepared to manage its aggressive growth.
✅ Choose This Plant If...
- You live in a warm climate and want a low-maintenance flowering plant for your garden.
- You want to attract butterflies and hummingbirds to your yard.
- You are experienced with managing aggressive spreaders.
- You have a sunny outdoor space where it can thrive.
- You appreciate its vibrant purple flowers.
❌ Skip This Plant If...
- You have pets who might ingest it.
- You live in a climate where it is considered invasive.
- You don't have a very sunny location.
- You are looking for a low-maintenance indoor plant.
Monkey Grass
Liriope muscariGardeners seeking a low-maintenance ground cover or border plant in outdoor landscapes.
✅ Choose This Plant If...
- You need a low-maintenance ground cover for your garden.
- You want to control erosion on a slope.
- You need a plant that is drought-tolerant once established.
- You want to suppress weeds in your garden beds.
- You need a plant that tolerates partial shade.
❌ Skip This Plant If...
- You have pets that might ingest it, as it is toxic.
- You are looking for an easy indoor plant, as it is challenging to grow indoors.
- You have limited space, as it can spread aggressively.
🎯 Quick Verdict
⚡ Key Differences Between These Plants
Mexican Petunia has fast growth, while Monkey Grass grows moderate; can spread via rhizomes..
💡 Pro Tips For Comparing These Plants
Mexican Petunia Care Tips
Mexican Petunia is primarily an outdoor plant that is difficult to maintain indoors. It requires very bright light, well-draining soil, and careful monitoring of its aggressive growth. It is toxic to pets, so caution is needed if kept indoors.
- Plant in a container to control its spread.
- Provide regular pruning to maintain its shape and size.
- Water deeply but infrequently.
- Fertilize during the growing season to encourage blooming.
- Monitor for pests and diseases and treat promptly.
Monkey Grass Care Tips
Liriope muscari is primarily an outdoor plant. Indoor cultivation is challenging due to its high light requirements and need for well-draining soil. It can be aggressive, spreading via rhizomes. Toxicity to pets is a significant concern.
- Plant in well-draining soil to prevent root rot.
- Water deeply but infrequently, allowing the soil to dry slightly between waterings.
- Fertilize in spring with a slow-release fertilizer.
- Divide clumps every few years to control spread and rejuvenate the plant.
- Monitor for pests and diseases, and treat promptly.
⚠️ Common Problems & Solutions — Plant Care Comparison
Mexican Petunia
Monkey Grass
❓ Frequently Asked Questions — Comparing These Plants
Mexican Petunia
What are the light requirements for Mexican Petunia?
Mexican Petunias thrive in full sun, requiring at least 6 hours of direct sunlight each day. Adequate sunlight is crucial for abundant blooming. However, they can also tolerate partial shade, especially in hotter climates, where some afternoon shade can prevent leaf scorch. Insufficient light can lead to leggy growth, reduced flowering, and paler foliage.
How do I care for Mexican Petunia?
Mexican Petunias are relatively easy to care for. Place them in a location that receives at least 6 hours of sunlight daily for optimal blooming. Water regularly, especially during hot, dry periods, keeping the soil consistently moist but not waterlogged. Fertilize every 4-6 weeks during the growing season (spring and summer) with a balanced, slow-release fertilizer or a liquid fertilizer formulated for flowering plants.
How do I propagate Mexican Petunia?
Mexican Petunias can be easily propagated through division, stem cuttings, and keiki (small plantlets that form on the stems).
Monkey Grass
What are the light requirements for Monkey Grass?
Monkey Grass thrives in bright, indirect light. While it can tolerate some shade, too little light can lead to leggy growth and reduced vibrancy. Avoid direct sunlight, especially during the hottest parts of the day, as it can scorch the leaves. East-facing windows are ideal, providing gentle morning light. North-facing windows can also work if the light is sufficient. If you notice the leaves fading or stretching towards the light source, move the plant to a brighter location. Consider using grow lights if natural light is insufficient, especially during winter months. Rotate the plant regularly to ensure even light exposure on all sides.
How do I care for Monkey Grass?
Monkey Grass is relatively easy to care for. Provide bright, indirect light for optimal growth. Water regularly, keeping the soil consistently moist but not waterlogged. Ensure good drainage to prevent root rot. Fertilize lightly during the growing season (spring and summer) with a balanced liquid fertilizer. Prune away any dead or damaged foliage to maintain its appearance and encourage new growth. Monkey Grass prefers temperatures between 60-75°F (15-24°C) and appreciates high humidity. Mist the foliage regularly or use a humidifier to increase humidity levels, especially in dry environments. Repot every 2-3 years as needed, using a well-draining potting mix.
How do I propagate Monkey Grass?
Monkey Grass can be propagated through division, stem cuttings, and air layering.
Last updated: May 6, 2026 — Plant care data reviewed and verified by our editorial team.