Lemon Grass: A Very Versatile Herb - Brooklyn Botanic Garden
Plants & Gardens Blog

Lemon Grass: A Very Versatile Herb

Taking care of the BBG Herb Garden is a diverse job: On a busy day it means about one-third actual gardening, one-third answering questions about our plants, and one-third listening to visitors' gardening tales—a problem with this year's tomatoes; a recipe for pesto; how they used sweet woodruff "in the old country."

Lemon Grass

Many visitors are not gardeners, but may be curious about the source of a favorite flavor or an herbal remedy; others want to show the kids the plants they grew up with around the house or farm. Still others are avid gardeners, collecting plant ideas, seed, and cuttings whenever available.

One of the herbs most asked about by visitors of all varieties is lemon grass, Cymbopogon citratus. Many associate it with Thai restaurants, and the scent of the rubbed leaves has inspired detailed recollections of mouth-watering dishes tried at some favorite dining spot. Visitors from Caribbean countries are sometimes surprised to see this tropical herb so far north of their homeland. Folks from India, China, and, of course, Southeast Asia also recognize it without needing to read the sign. Some do confuse the handsome gray-green foliage with that of citronella grass (C. nardus) a bigger, mustier-smelling relative, until they breath in its clean aroma—pure lemon, as the common name implies.

Some Like It Hot

Lemon grass is a tropical perennial, native to southern India, but cultivated outdoors in practically all tropical regions. In the United States, it is root-hardy to about USDA Zone 9 (California, central Florida) where it goes dormant during the mild winter. It grows in an ever-expanding clump, increasing slowly by tillering rhizomes, and reaches about six feet in height.

In northern regions it grows about three feet tall—more in a very hot summer. It is completely controllable in the cooler-climate garden because it is not winter-hardy.

It does best in full sun, in the hottest possible place, and likes plenty of water and a periodic light dose of fertilizer.

In northern climes, before killing frosts arrive, lemon grass should be cut back to eight-inch stubs, dug up, and potted for winter storage. You can pot excess growth for your friends at this time. If you are lucky enough to own a heated greenhouse, bring it in. The scented foliage will regrow quickly and you'll have a handy stash to use for flavoring winter recipes. Otherwise, store the potted clumps in the coolest part of the house or attached garage. Reduce watering to a bare minimum and let the clumps "hibernate." When they start to show signs of life in late winter, move them to a warm, sunny window and resume normal watering. In Brooklyn we plant our lemon grass in mid-May, after a two-week "hardening-off" in a shady, protected, outdoor spot.

Haute Cuisine and Home Remedies

Prapap's Chicken Coconut Soup

The more unusual ingredients from the list below can be found at an Asian market.

  • 1-1/2 cups chicken broth
  • 1 cup coconut milk
  • 6 thin slices young galanga
  • 2 stalks lemon grass, lower third only, cut into 1 inch lengths and crushed
  • 5 fresh caffre lime leaves, torn
  • (not cut) in half
  • 8 ounces boned chicken breast, sliced
  • 5 tablespoons fish sauce
  • 2 tablespoons sugar
  • 1/2 cup lime juice
  • 1 teaspoon black chili paste
  • 1/4 cup cilantro/coriander leaves, torn
  • 5 green Thai chili peppers, crushed

Bring chicken broth to a boil in saucepan, then add galanga, lemon grass, and lime leaves.Add coconut milk, chicken, fish sauce, and sugar.Simmer about four minutes, or until chicken is cooked.Place lime juice and chili paste in serving bowl, then pour soup into bowl.Garnish with cilantro and crushed chili peppers.Serves 4.

Lemon grass is cultivated commercially for its essential oil, which is used to scent soaps, detergents, and air fresheners, and from which constituent compounds are isolated and used in turn to produce commercial vitamin A and an artificial violet perfume. But the most practical home uses are culinary and medicinal.

Prapap Kongsmai, BBG's graphic artist, plant-label maker, and resident Thai chef, uses mainly the lower "stem" portion in his cooking. "When I owned a restaurant in Queens," he recalls, "some people wanted to return the soup. They said the lemon grass was too tough! I had to keep from laughing." In fact, only a cow could digest those stem segments—actually pseudostems, rolls of tough leaf sheaths that are finger-thick in lemon grass. During cooking the aromatic oil is released, giving dishes made with lemon grass their subtle citrus flavor. As for the visible portion that's impossible to chew? "Just leave it on your plate," Prapap recommends. So is there any part of lemon grass people actually eat? Prapap says that he occasionally uses the thinner leaf blades, sometimes slicing them paper-thin (across the grain) as an ingredient in a Thai seafood salad.

Roland Thomas of the BBG maintenance department comes to the rescue with another suggestion. Roland grew up on a farm on the island of Grenada and serves as BBG's unofficial chief advisor on tropical foods. "In my country we use the leaves, stems, everything. We chop it up and dry it, and make a tea for fever." Roland recommends boiling the lemon grass when using it as a fever remedy, but suggests merely steeping it to make refreshing tea. Use about two tablespoons per cup.

Seeds and Shoots

Visitors who ask me for seeds from our lemon grass are disappointed. The species flowers only rarely, and ours never has. However, seeds (which can be started on a windowsill) or plants are available from several nurseries (see box). Or, if you buy cut shoots of lemon grass at an Asian market, look to see if any true stem (where leaf sheaths are attached) is left intact at the base, below the pseudostem. If so, you can cut the leaves off short and "plant" the shoot in a pot of moist sand. It roots easily, and can be planted out in the garden where it will increase quickly in summer.

The fastest way to get a good crop, of course, is to divide a clump. Cut back the top, dig it up, and pry it apart. A fist-sized cluster of cut-back shoots with roots intact makes a nice division.

And let me end with a personal plea: If you visit the BBG Herb Garden, please don't ask for a division of our lemon grass. I'm not supposed to give samples. But I'll be more than happy to talk about it.

Seed Sources

Seeds for lemon grass can be purchased from the following nurseries:

  • Kurt Bluemel, Inc.: (410) 557-7229
  • Carroll Gardens, Inc.: (410) 848-5422
  • Edible Landscaping: (804) 361-9134
  • Goodwin Creek Gardens: (541) 846-7357
  • Logee's Greenhouses: (860) 774-8038
  • Louisiana Nursery: (318) 948-3696
  • Mellinger's Inc.: (330) 549-9861
  • Merry Gardens: (207) 236-9064
  • Shady Acres Herb Farm: (612) 466-3391
  • Sunnybrook Farms: (440) 729-7232
  • Thompson & Morgan: (732) 363-2225
  • White Flower Farm: (800) 411-6159
  • Wrenwood of Berkeley Springs (304) 258-3071

Robert Newgarden is a former gardener at Brooklyn Botanic Garden. He tended the Cashew Plant Family and other plant families in the Plant Family Collection. He also cared for the Herb Garden.

Comments will be posted after review; your email address will not be displayed. Have a gardening question for BBG staff? Reach out to our Gardener's Help Line.

Image, top of page: Antonio M. Rosario