Lemongrass is a tropical herb packed with strong citrus flavor. The lemon taste is prized in Asian cooking, as well as in teas, sauces, and soups. In the garden, lemongrass forms a tall, grassy clump 3 to 5 feet tall. Its appearance rivals that of many ornamental grasses and can easily fulfill a similar role in the landscape.
Soil, Planting, and Care
Lemongrass thrives in full sun, even in hot Southern locations. Give this herb rich, well-drained soil. Amend planting holes with composted manure to improve fertility and enhance the soil’s ability to hold water. If you’re adding several lemongrass plants to planting beds, space plants 24 inches apart.
Provide a steady supply of moisture for best growth—don’t let lemongrass roots dry out. Fertilize plants during the growing season every couple of weeks with a liquid plant food such as Bonnie Herb & Vegetable Plant Food or fish emulsion.
Plant lemongrass in a large pot that is at least 12 inches across, or use a 5-gallon bucket. Be sure to use a premium quality potting soil when growing lemongrass. Lemongrass grows tall, and pots can easily tip in windy weather, so place containers in a slightly protected location.
In cold regions, overwinter lemongrass indoors by digging up a few stalks, trimming them down to just a few inches tall, and planting them in smaller pots. Place them in a bright, south-facing window. Keep soil barely moist, as plants grow very slowly over winter. Another option is to store a pot of lemongrass, cut down, in a cool, dark place like a basement. Water just a few times over winter to keep roots alive. In spring, bring the pot into a bright spot, and resume normal watering. Shift outdoors when temperatures are above 40°F.
Due to its tropical nature, lemongrass usually only survives winters in zones 8 and warmer. In other areas, try growing lemongrass as an annual in planting beds or tucked into pots. This citrus-flavored grass overwinters well in a dormant state in a cool, dark spot indoors, or you can grow it as an indoor herb through winter in colder zones.
Few pests bother lemongrass. This herb is actually sometimes used in concoctions to repel insects. Occasionally, though, spider mites will attack plants overwintering indoors.
As lemongrass grows, it forms a tight clump that’s difficult to dig into. Use a sharp spade or hatchet to remove roots in early spring. Slice it like a pie, then pry slices of roots free. Keep an eye on plants in pots. With sufficient water, roots can quickly fill a too-small pot and burst it.
Harvest and Storage
Harvest lemongrass for its bulbous stem bases, rich with lemony flavor, or clip leaves for infusing tea and soup stock.
Start harvesting as soon as plants are 12 inches tall and stem bases are at least ½-inch thick. Cut stalks at ground level, or hand-pull entire stalks. You want to get the entire swollen base, which resembles a scallion or green onion. If a few roots come up with the stalk, don’t worry: It won’t harm the plant.
The edible portion of lemongrass is near the bottom of the stalk. Carefully cut off the grassy top part of the plant; use caution, as this can be razor-sharp at times. Leaves can be bundled and added to the liquid in a teapot or stock pot, then simmered to infuse lemon flavor into the brew.
Take the lemongrass base and peel the outer fibrous layer to expose the inner white, reedy part. To store, freeze this part either whole or chopped. To make slicing easier, first crush the stem base with the flat blade of a knife. The heart of the stalk (the part you want) has the consistency of soft butter and will then slice easily.
Lemongrass is best known for its use in Asian cuisine, especially Thai and Vietnamese. In the kitchen, use tender inner stalk bases in stir fries, salads, and sauces. To freeze lemongrass, store thinly sliced pieces in single layers in zipper-seal bags. To use, break off as much as you need for individual dishes. Or, freeze lemongrass minced or as a purée.
Leaves make a great addition to marinades and can be steeped in hot water for tea. After use, add leaves to your compost pile or puree them and scatter them in the grass along the edges of a patio or deck to help deter insects. To dry leaves, bundle them and hang them upside down in a dark place until dry. Store in tightly sealed jars. Dried lemongrass retains its flavor up to one year.