Lemongrass, Cymbopogon citratus, is a perennial grass prized for its lemony flavor in Asian cuisine, teas, and broths. Native to warm, humid regions, it is widely cultivated globally. Container gardening is a necessary method for growing lemongrass outside of frost-free zones, allowing the plant to be moved indoors for winter protection. When grown in a pot, the plant’s ultimate height is directly influenced by the container’s confines and the grower’s management practices.
Natural Growth Versus Potted Growth
In its native environment or when planted directly in the ground, lemongrass can develop into a massive clump. Provided with ample space, nutrients, and water, the plant can reach heights of up to six feet in a single growing season. This vigorous growth is driven by a sprawling root system, producing numerous thick, harvestable stalks.
Potted growth imposes a significant physical restriction on the plant’s size. The limited volume of soil and restricted root mass directly correlate to a reduction in vertical energy and overall biomass production. As a result, container-grown lemongrass typically achieves a more moderate height, generally falling within three to four feet.
The Role of Container Size on Final Height
The size of the container is the primary factor determining the final height and robustness of a potted lemongrass plant. Lemongrass is a heavy feeder that requires substantial root space to anchor itself and produce the thick stalks desired for cooking. Using a container that is too small triggers root restriction, which signals the plant to limit its growth above the soil line.
To achieve a moderate height of three to four feet with usable, half-inch-thick stalks, a minimum five-gallon planter is recommended. This size corresponds to a pot with a diameter of at least 12 to 14 inches. Such a container provides enough soil mass to retain adequate moisture and allows the dense, fibrous root system to develop sufficiently.
Choosing a smaller pot, such as one with only an 8- to 10-inch diameter, results in a stunted plant. In these restrictive conditions, the lemongrass may only reach one to two feet in height, yielding thinner and less vigorous stalks. The limited volume prevents the plant from generating the energy needed for substantial vertical growth, reducing productivity for culinary harvesting.
Environmental Factors Affecting Vertical Growth
Beyond the container’s physical size, several environmental factors influence the maximum height a potted lemongrass plant can achieve. Light exposure drives the photosynthesis required for vertical stretch and stalk development. Lemongrass requires a minimum of six to eight hours of direct sunlight daily to reach its height potential.
Plants placed in areas with lower light levels often exhibit a leggy growth habit, resulting in weaker, thinner, and shorter stalks. Consistent moisture and nutrient availability are also necessary for robust growth. Lemongrass is a thirsty plant during its active growing season, and water stress quickly results in stunted development.
A regular feeding schedule with a balanced, nitrogen-focused fertilizer is necessary for vertical growth in a container. Since the plant cannot draw on the nutrient reserves of garden soil, the limited potting mix must be replenished frequently. Applying a half-strength, water-soluble fertilizer every one to two weeks encourages the production of tall, grassy foliage and thickens the stalks.
Controlling Height Through Pruning and Harvesting
The gardener can reduce the height of an established potted lemongrass plant through harvesting. Frequent removal of the outer stalks is the most effective way to control the plant’s overall size and shape. Harvesting involves cutting individual stalks at the soil line when they reach a desired thickness, typically about a half-inch.
This process removes biomass, reducing the current height, and stimulates the plant’s basal meristems to produce new growth. Consistently harvesting the thickest stalks encourages the plant to grow outward into a bushier, denser clump rather than focusing energy on fewer, tall stalks.
Trimming the arching leaves is also a useful technique for maintaining a manageable profile and preventing the plant from flopping. The leaves can be cut back periodically to reduce the overall height by several inches without detriment to the plant’s health. Severe pruning, cutting the foliage down to a few inches above the stalk bases, is typically performed in early spring to remove old growth and prepare the plant for renewed vertical development.