Monkey Grass vs Penstemon Plant Comparison
Compare these two plants side by side — care needs, key differences, and which is right for your home.
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.
Penstemon
Penstemon spp.
Penstemon is a diverse genus of flowering plants, primarily herbaceous perennials, known for their vibrant, tubular flowers. They range in size from a few inches to several feet tall, with varying growth habits from upright to spreading. The flowers come in a wide array of colors, including shades of blue, purple, pink, red, and white, attracting pollinators like bees and hummingbirds. Penstemons are primarily grown outdoors in gardens and naturalized areas for their showy blooms, drought tolerance, and ability to attract wildlife. They are not typically grown indoors due to their high light requirements and need for specific environmental conditions.
Quick Plant Comparison
| Feature | Monkey Grass | Penstemon |
|---|---|---|
| Light | Full sun to partial shade outdoors. Requires very bright, direct light if attempted indoors. | Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal flowering. |
| Watering | 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. | Every 1-2 weeks, depending on weather and soil drainage. |
| Humidity | 40-60% | 30-50% |
| Temperature | 15-27°C | 15-27°C |
| Care Level | Expert | Expert |
| Growth Rate | Moderate; Can Spread Via Rhizomes. | Moderate |
| Max Height | Outdoors: 30-45 cm. Indoors (unlikely to thrive): 20-30cm | 0.3-1.2 meters (outdoors) |
| Pet Safety | ❌ Toxic To Pets | ❌ Toxic To Pets |
| Soil | Well-draining soil; sandy loam is ideal. Avoid heavy clay soils. | Well-draining soil, such as a sandy or gravelly loam. Avoid heavy clay soils. |
| Beginner Friendly | ❌ No | ❌ No |
| Weekly Maintenance | 10 minutes weekly (mostly weeding around the plant) | 15 minutes weekly (outdoor) |
🔬 Botanical Information — Comparing These Plants
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. |
Penstemon
| Scientific Name | Penstemon spp. |
|---|---|
| Family | Plantaginaceae |
| Native To | North America, particularly western North America |
| Also Known As | Beardtongue, Penstemon |
| Leaves | Leaves are typically lance-shaped to oval, arranged oppositely along the stem. They can be smooth or slightly hairy, and vary in color from green to bluish-green. Leaf size varies depending on the species. |
| Flowers | Penstemon rarely flowers indoors due to insufficient light. Outdoors, they produce showy, tubular flowers in a wide range of colors, including blue, purple, pink, red, and white. Flowers are arranged in clusters or spikes at the ends of stems. |
📏 Size & Growth — Plant Comparison
Monkey Grass
Penstemon
🌱 Propagation — Comparing Plant Growth
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.
Penstemon
Methods: Seed, stem cuttings, division
Difficulty: Moderate
Tips: For stem cuttings, take cuttings in late spring or early summer and root them in well-draining soil. Division can be done in early spring or fall. Seeds can be sown in spring or fall.
✨ Benefits & Features — Comparing Plant Value
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
Penstemon
Penstemon's tubular flowers are specifically adapted for pollination by bees and hummingbirds, showcasing a co-evolutionary relationship. The sterile stamen, or beardtongue, is a distinctive feature of the genus. Many species are native to specific regions and play important roles in local ecosystems.
- ✓ Attracts pollinators, supporting local ecosystems.
- ✓ Adds vibrant color and visual interest to gardens.
- ✓ Drought-tolerant, reducing water consumption.
- ✓ Relatively deer resistant, protecting from browsing.
- ✓ Provides a source of nectar for hummingbirds and bees.
- ⚠️ Toxic to pets
📅 Maintenance Schedule — Plant Care Comparison
Monkey Grass
Penstemon
🌞 Light Requirements
Monkey Grass
Full sun to partial shade outdoors. Requires very bright, direct light if attempted indoors.
Low light tolerant: ❌ No
Penstemon
Full sun to partial shade. Requires at least 6 hours of direct sunlight daily for optimal flowering.
Low light tolerant: ❌ No
💧 Watering Needs
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.
Penstemon
Water deeply when the top inch of soil is dry. Avoid overwatering, as Penstemons are susceptible to root rot. Allow the soil to dry out slightly between waterings. Signs of overwatering include yellowing leaves and wilting, while underwatering can cause leaf drop and stunted growth.
🌡️ Temperature & Humidity
Monkey Grass
Temperature: 15-27°C
Humidity: 40-60%
Penstemon
Temperature: 15-27°C
Humidity: 30-50%
🤔 Which Plant Is Right For You?
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.
Penstemon
Penstemon spp.Gardeners looking for drought-tolerant, pollinator-attracting plants for sunny locations.
✅ Choose This Plant If...
- You want to attract hummingbirds and bees to your garden.
- You need a drought-tolerant plant for a sunny location.
- You desire a long-blooming perennial with vibrant colors.
- You want a plant that is relatively deer resistant.
- You are looking for a native plant to support local ecosystems.
❌ Skip This Plant If...
- You have pets that may ingest the plant.
- You cannot provide at least 6 hours of direct sunlight daily.
- You live in a humid climate with poorly draining soil.
🎯 Quick Verdict
⚡ Key Differences Between These Plants
Monkey Grass has moderate; can spread via rhizomes. growth, while Penstemon grows moderate.
💡 Pro Tips For Comparing These Plants
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.
Penstemon Care Tips
Penstemon is primarily an outdoor plant that requires full sun and well-draining soil. It is not well-suited for indoor growing due to its high light requirements and need for specific environmental conditions. Indoor attempts are likely to fail without supplemental lighting and careful monitoring of soil moisture.
- Plant in well-draining soil to prevent root rot.
- Provide at least 6 hours of direct sunlight daily for optimal flowering.
- Deadhead spent flowers regularly to encourage more blooms.
- Water deeply but infrequently, allowing the soil to dry out slightly between waterings.
- Apply a balanced fertilizer in early spring before new growth begins.
⚠️ Common Problems & Solutions — Plant Care Comparison
Monkey Grass
Penstemon
❓ Frequently Asked Questions — Comparing These Plants
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.
Penstemon
What are the light requirements for Penstemon?
Penstemon requires at least six hours of direct sunlight per day to thrive and produce abundant blooms. A location with full sun exposure is ideal. If growing Penstemon indoors, place it near a sunny window, preferably a south-facing one. Insufficient light can result in leggy growth, reduced flowering, and pale foliage. In hot climates, some afternoon shade may be beneficial to prevent scorching. Rotate the plant regularly to ensure even light exposure on all sides. Consider using grow lights to supplement natural light during the darker months of the year, especially for indoor plants.
How do I care for Penstemon?
Penstemon thrives in well-draining soil and prefers full sun, although some varieties can tolerate partial shade. Water regularly during the first growing season to establish a strong root system, then reduce watering frequency as the plant matures. Avoid overwatering, as this can lead to root rot. Fertilize in early spring with a balanced fertilizer to promote healthy growth and abundant blooms. Deadhead spent flowers to encourage continuous blooming. Prune back in late fall or early spring to maintain shape and remove any dead or damaged growth. Provide good air circulation to prevent fungal diseases. Mulch around the base of the plant to conserve moisture and suppress weeds. Penstemon is generally hardy but may benefit from winter protection in colder climates.
How do I propagate Penstemon?
Penstemon can be propagated by division, stem cuttings, and seeds.
Last updated: May 11, 2026 — Plant care data reviewed and verified by our editorial team.