Lemongrass (Cymbopogon citratus) is a tropical, clumping grass prized for its aromatic, citrus-flavored stalks used in cooking and herbal remedies. As a vigorous perennial, it forms dense, widening clumps that eventually lead to overcrowding and reduced air circulation. To invigorate the plant and prevent it from becoming rootbound, especially in containers, replanting and division are necessary maintenance steps, typically every one or two years. Dividing the established root mass into smaller, healthy sections is the most effective way to multiply the plant and ensure continued, robust growth.
Essential Preparation and Timing
The ideal time to replant lemongrass is during the late spring or early summer, just as the plant begins its period of active growth. Transplanting during this phase allows the divided sections to establish new roots quickly in the warm soil before the peak heat of summer or cooler weather arrives.
A clean, sharp knife, a serrated kitchen knife, or a sharp spade is necessary for making clean cuts through the dense root ball. You will also need new potting soil or soil amendments, like compost, to refresh the planting medium in the new location or container. A day or two before the planned division, thoroughly water the existing lemongrass clump to make the root ball more manageable to dig up and separate, reducing transplant shock.
If you are moving the divisions into pots, ensure the containers are appropriately sized and have excellent drainage holes. For in-ground planting, the new location should be prepared by loosening the soil to a depth of 8 to 12 inches and incorporating compost or organic matter. This ensures the new planting site is ready to receive the divisions immediately, minimizing the time the roots are exposed.
Dividing and Transplanting the Lemongrass Clump
The replanting process begins with carefully extracting the entire established clump from its current location. If the plant is in a pot, gently tilt the container and slide the root ball out. For in-ground plants, dig a wide circle around the perimeter of the clump to preserve the root system. Once the root ball is free, use your sharp tool to slice the mass into smaller, viable sections.
The goal in division is to create sections, often called culms, each possessing a healthy portion of roots and several strong stalks. Slice the root ball like a pie, ensuring each piece has an intact root system for successful establishment. Before planting, trim the top foliage down to about 6 inches; this reduces the amount of moisture the roots must support immediately after being moved.
When planting the new divisions, ensure the new hole or container is deep enough to accommodate the root mass without bending or circling the roots. Position the division so that the root crown—the point where the stems meet the roots—is level with the surrounding soil surface. Backfill the hole or container with the prepared soil, gently tamping the medium around the roots to eliminate air pockets and secure the new plant.
Ensuring Successful Establishment
Immediately following transplanting, the newly divided lemongrass requires a deep, thorough watering to help the soil settle firmly around the roots. This initial saturation minimizes the shock the plant experiences. For the first few weeks, maintaining consistently moist soil is the most important factor for encouraging new root growth and successful establishment.
For the initial recovery period, place container-grown divisions in a location that receives partial shade, especially if the sun is intense. Although lemongrass thrives in full sun, temporary shade prevents the foliage from drying out before the roots can take up enough water. After one to two weeks, gradually move the plant back to a spot that receives six to eight hours of full sun daily.
Monitor the divisions closely for signs of new growth, which indicates the plant has successfully established itself. Continue with a consistent watering schedule, ensuring the soil remains damp but not waterlogged, particularly during dry spells. Once established, the lemongrass will resume vigorous growth, and you can transition back to its regular care routine.