Cymbopogon citratus (Lemon Grass): Complete Grass Growing Guide
Cymbopogon citratus
Cymbopogon citratus (Lemon Grass) (Source: wikimedia)
1. Introduction & Taxonomy
Cymbopogon citratus is one of the world's most beloved aromatic plants, filling kitchens across Southeast Asia with its bright, citrusy fragrance and gardens with its graceful, fountain-like form. Lemon Grass transcends its role as a mere culinary herb to serve as an ornamental grass, a medicinal plant, and even a natural insect repellent, making it one of the most versatile grasses in cultivation. Its swollen stem bases, bursting with lemon-scented essential oils, are the heart and soul of Thai, Vietnamese, and Indonesian cuisines.
Cymbopogon citratus is a densely clumping, aromatic perennial grass that grows 1 to 1.8 meters tall, forming robust tussocks of long, arching, strap-like leaves. The leaves are pale to medium green, up to 90 cm long and 2 cm wide, with a prominent central vein and rough margins. The swollen, bulbous stem bases are the primary culinary part, consisting of tightly wrapped leaf sheaths that are white to pale green with a purple tinge. When crushed, all parts of the plant release a strong, fresh lemon scent due to the high concentration of citral, the essential oil compound responsible for its characteristic fragrance. The plant rarely flowers in cultivation outside the tropics.
Taxonomic Classification
Habitat and Distribution
Cymbopogon citratus is believed to be native to southern India and Sri Lanka, though its exact origin is uncertain due to millennia of cultivation. It thrives in tropical and subtropical climates with high rainfall, growing naturally in moist, fertile soils in open or semi-shaded conditions.
Botanical Note: Poaceae (the grass family) is one of the largest and most ecologically important plant families, with over 12,000 species worldwide. True grasses have hollow, jointed culms (stems), narrow leaves with parallel veins and a distinctive ligule where the blade meets the sheath, and flowers reduced to spikelets arranged in panicles, racemes, or spikes. Ornamental grasses from this family are prized for their graceful movement, feathery inflorescences, and seasonal colour changes.
Native Range & Distribution Map
The map below shows the native range and notable cultivation regions for Cymbopogon citratus.
2. Biology & Morphology
<\!-- SIZE_COMPARISON_SVG -->Growth Form & Architecture
Cymbopogon citratus is a tussock-forming true grass (Poaceae) that develops dense, mound-like clumps of foliage with hollow, jointed culms.
Species-Specific Morphology
Cymbopogon citratus is a densely clumping, aromatic perennial grass that grows 1 to 1.8 meters tall, forming robust tussocks of long, arching, strap-like leaves. The leaves are pale to medium green, up to 90 cm long and 2 cm wide, with a prominent central vein and rough margins. The swollen, bulbous stem bases are the primary culinary part, consisting of tightly wrapped leaf sheaths that are white to pale green with a purple tinge. When crushed, all parts of the plant release a strong, fresh lemon scent due to the high concentration of citral, the essential oil compound responsible for its characteristic fragrance. The plant rarely flowers in cultivation outside the tropics.
Inflorescence & Flower Structure
Grass flowers are highly reduced and arranged in spikelets, with wind pollination as the primary reproductive strategy.
Key Characteristics
- Height: 0.5-2m
- Growth Habit: Tussock-forming
- Growth Rate: Fast under optimal conditions
- Life Cycle: Perennial
- Toxicity: Cymbopogon citratus is generally regarded as safe for culinary and medicinal use. The essential oil can cause skin irritation in sensitive individuals when applied undiluted. The leaves have sharp edges that can cause minor cuts.
- Conservation Status: Least Concern. Cymbopogon citratus is widely cultivated throughout the tropics and subtropics and faces no conservation threats. Its wild origin is obscured by long cultivation history.
3. Reproduction & Propagation
<\!-- PROPAGATION_METHODS_SVG -->Primary propagation methods for Cymbopogon citratus: Seed or vegetative division.
Propagating Cymbopogon citratus
Lemon grass is most easily propagated by division of established clumps. In spring or early summer, separate the outer stalks with their roots from the main clump and replant immediately. Each division should have at least 3 to 5 stalks with roots attached. Alternatively, purchased stalks can be rooted in water by placing them in a glass on a sunny windowsill; roots typically appear within 1 to 3 weeks. Seed propagation is possible but much slower; sow seeds on the surface of warm, moist compost and keep at 20 to 25 degrees Celsius until germination, which takes 14 to 21 days.
Vegetative Propagation
Propagated by clump division in spring or early summer.
Propagation Tip: Division of established clumps in spring gives the fastest results.
4. Cultivation Requirements
<\!-- CULTIVATION_SVG -->Soil / Substrate
Well-draining, moderately fertile soil. A mix of garden loam, compost, and coarse sand.
Watering
Medium to high. Lemon grass prefers consistently moist soil and benefits from regular watering, especially during active growth. It tolerates brief dry spells but produces the best growth and most aromatic stems with ample moisture.
Light Requirements
Full sun to partial shade. Most ornamental grasses perform best in full sun with at least 6 hours of direct light daily.
Temperature
- Optimal Growth: 18-30°C (65-86°F)
- Minimum Tolerance: -29°C (-20°F)
- USDA Hardiness: Zones 5-9
Fertilization
Apply a balanced slow-release fertilizer in spring. Most grasses are light feeders.
Common Cultivation Mistake: Over-watering and over-fertilizing promote weak, floppy growth. These plants prefer lean conditions.
Seasonal Care Calendar
Follow this season-by-season guide for optimal care timing throughout the year.
🌱 Spring (March–May)
Divide and replant overgrown clumps. Begin regular watering and feeding as growth resumes. Move container-grown plants outdoors after frost danger has passed.
☀️ Summer (June–August)
Harvest stems regularly for culinary use by cutting at the base. Water deeply during dry periods. Feed with nitrogen-rich fertilizer monthly for maximum growth.
🍂 Fall (September–November)
Take final harvests before frost. In temperate climates, pot up a few divisions and bring indoors for winter. Reduce watering for outdoor plants as growth slows.
❄️ Winter (December–February)
In tropical climates, growth continues year-round. In temperate zones, protect outdoor plants with thick mulch or move containers to a frost-free location. Indoor plants need bright light and minimal water.
5. Diseases & Pests
Below are the most common pests and diseases affecting Cymbopogon citratus and how to manage them.
Rust
Puccinia rust can appear as orange-brown pustules on leaves in humid conditions, causing premature leaf drop if severe.
Leaf blight
Helminthosporium leaf blight causes brown, elongated lesions on leaves during warm, wet weather and can spread quickly in dense plantings.
Red spider mite
Spider mites can infest plants in dry, indoor conditions, causing yellowing and stippling of the foliage.
Mealybugs
White, cottony mealybug colonies may develop in the tight leaf sheaths near the base, weakening the plant and producing sticky honeydew.
IPM: (1) Choose the right species for your conditions. (2) Maintain good air circulation. (3) Cut back dead foliage in late winter. (4) Most ornamental grasses are remarkably pest-free when well-sited.
6. Indoor Growing Guide
Cymbopogon citratus can be grown in containers and brought indoors during winter in cold climates.
Container Selection
Use containers with adequate drainage holes. Terra cotta pots provide good drainage and stability.
Indoor Light
Place in the brightest available location. Most grasses need at least 4-6 hours of direct or bright indirect light.
Indoor Success Key: Bright direct light is the single most important factor for growing grasses indoors.
7. Landscape Use & Design
Cymbopogon citratus provides graceful movement, fine texture, and seasonal interest in the landscape.
Design Applications
- Herb and kitchen garden
- Tropical-style border
- Container planting for patios
- Fragrant garden
- Edible landscape
- Insect-repellent garden border
Companion Planting
These species pair well with Cymbopogon citratus in garden settings:
- Ocimum basilicum (Thai basil)
- Capsicum annuum (chili pepper)
- Zingiber officinale (ginger)
- Citrus limon
- Galangal
- Kaffir lime
Design Principle: Ornamental grasses are at their most magical when backlit by low sun. Position where morning or evening light illuminates inflorescences from behind.
8. Cold Climate Strategies
Cymbopogon citratus shows good cold tolerance and can be grown outdoors year-round in many temperate climates.
Hardiness Thresholds
- USDA Zones: 5-9
- Minimum Survival Temperature: -29°C (-20°F)
Overwintering Options
- Leave in Place (hardy species): Cut back dead foliage in late winter. Apply 5-10 cm of mulch around the crown.
- Container Culture: Move potted plants to a frost-free location for winter.
- Mulching: Apply thick straw or bark mulch over the crown after the first hard frost.
Winter Survival Rule: Most grass losses occur from wet cold. Ensure excellent drainage through winter.
Winter Care Tip: In tropical climates, growth continues year-round. In temperate zones, protect outdoor plants with thick mulch or move containers to a frost-free location. Indoor plants need bright light and minimal water.
9. Ethnobotany & Cultural Significance
Lemon Grass is inseparable from the culinary traditions of Southeast Asia, where it has been used for centuries as a fundamental flavoring in soups, curries, teas, and stir-fries. In traditional medicine systems across Asia, Africa, and the Caribbean, it is used to treat fevers, digestive problems, and anxiety, earning it the common name 'Fever Grass' in Jamaica and other Caribbean nations. The essential oil industry extracts massive quantities of lemon grass oil for use in perfumes, cosmetics, cleaning products, and aromatherapy. In India, it has cultural significance in Ayurvedic practice and is grown commercially on a vast scale.
Conservation Note: Many grass, sedge, and rush species play critical ecological roles as habitat providers, soil stabilizers, and water filtration agents. By growing Cymbopogon citratus, you contribute to maintaining awareness of these often-overlooked botanical workhorses.
Did You Know?
- Lemon grass contains up to 80% citral in its essential oil, which is the same compound that gives lemons their characteristic scent.
- India produces approximately 80% of the world's lemon grass oil, harvesting the leaves multiple times per year from commercial plantations.
- In Brazilian folk medicine, lemon grass tea (cha de capim-limao) is so popular that it is one of the most commonly consumed herbal teas in the country.
- A single mature lemon grass clump can produce 50 or more harvestable stalks per season, making it one of the most productive herbs per square meter.
Frequently Asked Questions
Can I grow lemon grass from grocery store stalks?
Yes, this is one of the easiest ways to start lemon grass. Look for stalks with intact bases, place them in a jar of water on a sunny windowsill, and roots will develop within 1-3 weeks. Once roots are well-established, plant in soil.
Does lemon grass repel mosquitoes?
The essential oil citronellal found in lemon grass does repel mosquitoes, but simply growing the plant nearby is not very effective. The leaves need to be crushed or the oil extracted and applied to release the repellent compounds in sufficient concentration.
Is lemon grass perennial?
Lemon grass is a tender perennial (USDA zones 10-11) that is killed by frost. In colder climates, it is grown as an annual or overwintered indoors. With protection, it can survive in zone 8b-9 as a die-back perennial.
How do I harvest lemon grass for cooking?
Grasp a stalk at the base and twist it firmly while pulling. The bulbous lower 10-15 cm of the stalk is the part used in cooking. Peel away the tough outer layers to reveal the tender, aromatic core. Fresh stalks can be refrigerated for 2-3 weeks or frozen for months.
Summary & Key Takeaways
Cymbopogon citratus, is a tussock member of the genus Cymbopogon (Poaceae), native to southern India and Sri Lanka. It shows good cold tolerance, making it suitable for temperate gardens.
Key Points to Remember:
- Propagation: Seed or clump division
- Light: Full sun for most species
- Substrate: Well-draining, moderately fertile
- Watering: Moderate — avoid overwatering
- Hardiness: USDA Zones 5-9, minimum -29°C (-20°F)