If you’ve ever grown this striking and flavorful herb, you may have wondered “Is lemongrass a perennial? And if it is, can I overwinter it?” You’re not alone in asking yourself these questions; I’ve heard them cross the lips of many gardeners over the years. Lemongrass is such a versatile herb and a beautiful plant. It’s no wonder folks want to know how to keep it around from one year to the next. This article shares details on where lemongrass survives the winter (hint: where it’s warm!) and offers you advice on keeping lemongrass plants alive during the colder months, even if you don’t live in a warm climate.
A quick introduction to lemongrass
The scent and flavor of lemongrass leaves and stems is an essential ingredient in recipes from around the world. There are two common species of lemongrass. One is edible, the other is not.
- West Indian lemongrass (Cymbopogon citratus) is indigenous to Southeast Asia but has been introduced to various tropical growing regions around the world. It is grown as a commercial food crop in Thailand, Sri Lanka, Indonesia, India, and other tropical regions.
- The second species of lemongrass is known as citronella grass (Cymbopogon nardus). It too is indigenous to tropical regions of the Asian continent, however it is not edible. Instead, citronella grass is grown for its essential oil (known as citronella oil) that is used in insect repellents, including citronella candles and other mosquito repelling products. In some regions it is considered an invasive plant.
The species you want to grow for culinary enjoyment is West Indian lemongrass, Cymbopogon citratus, and you’ll find the plant for sale at nurseries and garden centers around the world, typically alongside classic herbs, like thyme, oregano, and rosemary.
Does lemongrass survive the winter?
Lemongrass plants are true perennials with life cycles that continue for many years if the plant is grown where temperatures stay above freezing year-round. Though they are perennial, lemongrass is not frost tolerant. So, if you live in a climate where winter temps regularly drop below freezing, lemongrass is treated like other annuals and only grown for a single season. The plants are then fully harvested and removed from the garden prior to the onset of cold temperatures. Or, they are left in the garden to die with the arrival of the first frost. However, if you don’t want to fully harvest or toss your plant at the end of the season, there are a few clever ways you can keep your lemongrass plants from one year to the next. Later in this article, I’ll share two ways to overwinter lemongrass, no matter where you live.
Is lemongrass a perennial where you live?
Since the cold tolerance of lemongrass is pretty much non-existent, the only growing zones here in the US where it’s a sure-fire outdoor perennial are USDA Zone 9 and Zone 10. Globally, the closer you live to the equator, the more likely the plant is to survive outdoors year-round. It’s a tropical plant, after all, so those are the climates in which you’ll have the most success.
That being said, throughout the summer months, when temperatures and humidity are high, lemongrass does beautifully in cold climates, so just because it isn’t winter hardy where you live, doesn’t mean you shouldn’t grow it. The plants look a lot like an ornamental grass and are well worth including in your garden, even if you aren’t interested in overwintering them.
Where to grow lemongrass
Lemongrass performs best in full sun conditions, but it does tolerate some shade. In well-drained soil, the clumps can grow quite large over the course of a single growing season. Most gardeners are surprised that the tiny two-inch-tall plant they settle into the garden in late May is three feet tall and equally as wide just a few months later. Incorporate compost or another source of organic matter into the planting site or grow lemongrass in a container filled with high-quality potting soil blended 50/50 with compost. Potted lemongrass plants make a lovely addition to patios, decks, porches, and vegetable gardens.
Ways to overwinter lemongrass plants
If you live in a cold climate where the plants will not survive outdoors, there are two ways to overwinter lemongrass plants. Their survival depends on a combination of your good timing and the conditions you subject the plants to. The first way to overwinter lemongrass plants is indoors, in a pot as a houseplant. The second involves keeping a few rooted bare-root stems in a glass of water through the winter months. Let me explain each of these two methods to you in greater detail.
Is lemongrass a perennial you can grow indoors as a houseplant? Yes!
If you want to overwinter lemongrass as a houseplant, plan to dig it out of the garden a few weeks before your first frost and pot it up into a container filled with new, sterile potting soil. Plastic or glazed ceramic pots are best. Avoid terracotta because it will dry out too quickly inside your home. If you’d like, this is a good time to divide the plant and pot each division into its own container so you’ll have more plants in the spring. Alternatively, you can harvest up to three-quarters of the plant and only save a small chunk of it to grow as a houseplant. Place the newly planted pot (or pots) in a shady area to allow the plant(s) time to settle into its new home until the danger of frost threatens. If you’re already growing your lemongrass plant in a pot, you can skip this step.
When frost is on the immediate horizon, bring the pot indoors. Place it in a bright, south-facing window or under a grow light. Remember, these are tropical plants that require a lot of light. They also prefer humid conditions, which is not likely to be what you have inside of your home during the winter months. Because of this, consider placing the pot on a humidity tray or near a humidifier. Keep the soil moisture level even; never allow the plant to fully dry out. Do not apply fertilizer in the winter as they plants are not actively growing and do not require nutrients.
Throughout the winter, if the ends of the leaves or shoots turn brown or crispy, don’t hesitate to trim them off. Sometimes the plant appears to die back, but as long as the “hearts” of each of the stems remain flexible and green, the plant will survive the winter.
Thankfully, lemongrass plants are not a favorite of pests, so it isn’t likely that you’ll face pest issues when growing lemongrass indoors for the winter.
Refrain from harvesting during the winter because it will reduce the plant’s chances of survival. Make your harvests when you pot the plant prior to bringing it indoors.
Keeping a lemongrass plant in water
Another fun way to overwinter a lemon grass plant is to keep a “sprig” of it in a glass of water on the windowsill. To do this, crack off an entire stalk from the mother plant and keep a few small roots intact. Trim down the leaves, rinse off the roots, and drop the base of the stem into a shallow glass of water. Wash the glass and replace the water once every week to ten days throughout the winter and trim off any new leaves that grow too long and spindly.
Choose a west-facing window if possible so the lemongrass sprig receives good light, but not intense light. This is a fun way to help lemongrass plants survive cold winters. You can overwinter as many lemongrass sprigs as you’d like. The roots will grow in the water all winter long (don’t hesitate to trim them a bit if they get too long).
Come late winter, pot each sprig up into its own small pot and move them to a south-facing window or under grow lights about 6 weeks before your last spring frost. Then, when the danger of frost has passed, you can plant your lemongrass “babies” outdoors.
Is lemongrass a perennial you can put into dormancy?
While many different tropical perennial plants can be kept in a dormant state through the winter, lemongrass cannot. It does not have a natural dormancy period and will likely die if you try to overwinter it in a dark garage, basement, or root cellar. However, dormancy is a great way to overwinter other tropical plants, like elephant ears, cannas, hibiscus, red Abyssinian bananas, and more.
Harvesting lemongrass at the end of the season
If you don’t have the interest or ability to keep your lemongrass beyond a single growing season, then harvest the stalks to flavor soups, Thai curry dishes, and stir fries. The intense lemon flavor can’t be beat. Here is an extensive article on how to harvest lemongrass, peel off the out layers prior to use, and even how to freeze the stalks for winter cooking.
Now that you know the answer to the question “Is lemongrass a perennial,” don’t be afraid to experiment with different overwinter techniques. And, if you’re lucky enough to have a heated greenhouse, you can also try keeping lemongrass over the winter there, too.
For more on growing unusual herbs, please visit these articles:
- Vietnamese coriander
- How to grow saffron
- Growing wasabi and horseradish
- How to grow mint indoors
- Herbs for a tea garden
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