Lemongrass, a tropical perennial grass (Cymbopogon genus), is valued for its fragrant, lemon-scented stalks and leaves. It is popular in both culinary arts and essential oil production. As a fast-growing plant, gardeners often inquire about the maximum size it can attain, which depends on several factors.
The Standard Height Range of Lemongrass
When grown in optimal conditions, mature lemongrass typically reaches a height between three and six feet. Exceptional specimens in tropical environments have been documented to grow as tall as eight feet. Lemongrass is a tussock-forming plant, characterized by dense, ever-expanding clumps rather than a single stem. While the stalks grow vertically, the base of the plant can spread significantly, often reaching two to three feet in diameter. It generally achieves its full height potential within six to ten months after planting.
Environmental Factors That Determine Size
Sunlight exposure is a primary determinant of whether a lemongrass plant achieves the upper limits of its height potential. Full, direct sunlight for at least six to eight hours per day is mandatory for robust growth and maximum vertical extension. Plants grown in partial shade often become leggy and fail to develop the dense, upright structure characteristic of tall, healthy specimens.
The availability of water significantly influences the plant’s ability to sustain rapid, tall growth. As a tropical grass, lemongrass requires consistent and abundant moisture throughout its entire growing season. Periods of drought or inconsistent watering will quickly stunt the plant, causing the leaves to curl and limiting the overall height it can achieve before maturity.
Soil composition and nutrient availability also influence stature. Lemongrass thrives in rich, loamy, well-draining soil high in organic matter. A steady supply of nitrogen is particularly important, as this nutrient fuels the production of chlorophyll and leafy biomass. High nitrogen promotes longer leaf blades and thicker stalk development, pushing the plant toward its maximum genetic size. Poor, compacted, or nutrient-deficient soils compromise the structural integrity and growth rate, resulting in a significantly shorter plant.
Distinguishing Common Lemongrass Varieties
Not all lemongrass plants share the same genetic blueprint, leading to differences in maximum height. The two most common species are Cymbopogon citratus and Cymbopogon flexuosus.
Cymbopogon citratus (West Indian Lemongrass)
This variety is most frequently used in cooking due to its thicker, more bulbous stalk base and milder flavor. It typically stays within the lower to middle range of the standard height, often maxing out around four or five feet. Its stature is generally denser and more compact.
Cymbopogon flexuosus (East Indian Lemongrass)
This species is primarily cultivated for its higher yield of essential oils and is less favored for culinary use. It usually exhibits a taller, more slender growth habit and is more likely to reach the six- to eight-foot extreme of the height range.
Cultivation Practices and Height Management
Regular harvesting is one of the primary human interventions that manages the perceived size and shape of the plant. Cutting the outer stalks near the ground encourages the plant to produce new, vigorous growth from the center of the clump. While this practice maintains the plant’s health, it keeps the overall height of the usable stalks below the maximum potential.
Allowing the clump to become overly dense negatively affects individual stalk height and vitality. Lemongrass should be divided every few years to prevent overcrowding, which forces the plant to compete for light and nutrients. When roots become pot-bound, stalks often remain thin and stunted. Dividing the root ball invigorates the plant and ensures new growth can achieve its full stature.
In temperate climates, the practice of overwintering also influences the plant’s annual height potential. Bringing the plant indoors or heavily mulching it in the ground often results in a period of dormancy or reduced growth. The plant must then restart its entire growth cycle in the spring, typically limiting its ability to reach maximum heights during the single growing season.