At a glance
| Botanical name | Cymbopogon citratus |
|---|---|
| Family | Poaceae (grass family) |
| Type | Tender perennial grass; summer annual in cold zones |
| USDA zones | Reliably perennial in about 9–11; NC State lists 8b–11 |
| Mature size | 2–4 ft tall, 2–3 ft wide (NC State); up to 6 ft in ideal conditions (UF/IFAS) |
| Light | Full sun |
| Soil | Moist, well-drained; tolerates a range of soil types |
| Spacing | About 3 ft (UF/IFAS) |
| Propagation | Division, nursery plants or rooted stalks; rarely grown from seed (UF/IFAS) |
| Harvest | Stalks ½ inch or thicker, cut at ground level |
| Pets | Toxic to dogs, cats and horses per ASPCA |
What lemon grass is (and what it isn't)
Lemon grass, usually written lemongrass, is Cymbopogon citratus, a clumping tropical grass grown for its lemon-scented stalks and leaves (NC State Extension). The pale, thick lower stalk is the part used in Thai, Vietnamese and other Southeast Asian cooking; the long, blade-like leaves are used for tea and infusions.
Several lemon-scented plants get confused with it:
| Plant | What it is | How to tell |
|---|---|---|
| Lemongrass (Cymbopogon citratus) | Tropical clumping grass; the culinary species | Thick, bulb-like white-to-pale-green stalk bases; long arching leaves with a strong lemon scent |
| East Indian lemongrass (C. flexuosus) | Related grass; UF/IFAS notes East Indian and West Indian (C. citratus) lemongrass are both used for cooking | Seed sold simply as "lemongrass" may be this or another Cymbopogon species; check the botanical name |
| Citronella grass (C. nardus, C. winterianus) | Related grass grown for citronella oil | Similar look; grown for oil, not the cooking herb |
| Lemon verbena (Aloysia citrodora) | Woody shrub | Narrow leaves on branching stems, not a grass |
| Lemon balm (Melissa officinalis) | Mint-family perennial | Square stems, oval toothed leaves; hardy in cold climates |
For the everyday kitchen herbs, see growing herbs outdoors.
Is lemongrass a perennial?
Yes, but only where it doesn't freeze hard. Lemongrass is a tender perennial: it keeps coming back year after year in frost-free or nearly frost-free climates, and dies when the clump freezes. NC State Extension lists USDA zones 8b through 11. UF/IFAS Gardening Solutions describes it as an herbaceous perennial in Florida whose leaves stay green most of the year, and UF/IFAS Extension Nassau County notes that cooler areas grow it as an annual.
| USDA zone | How it behaves | What to do |
|---|---|---|
| 3–7 | Summer annual; killed by fall frost | Plant out after frost; harvest all season; dig and overwinter indoors or start fresh next spring |
| 8 | Borderline; NC State's range starts at 8b, so it may survive mild winters with top growth killed | Plant in a warm, sheltered spot with heavy mulch, and keep a backup division indoors |
| 9–11 | Evergreen or returning perennial | Grow in the ground; divide crowded clumps; cut back any frost-burned leaves in spring |
Not sure of your zone? Use the zone finder.
How to grow lemongrass: step by step
- Get a plant or root a stalk. UF/IFAS notes lemongrass is rarely grown from seed; it is usually started from divisions or nursery plants. Fresh grocery-store stalks with the base intact often root: stand them in a few inches of water in a bright window, change the water every few days, and pot them up once roots are an inch or two long, typically in a few weeks.
- Wait for warm weather. Plant divisions outdoors after frost danger has passed (UF/IFAS), once nights stay above about 50°F; PlantVillage gives a tolerated range of about 50–91°F, with best growth at 77–86°F. Lemongrass sits still in cold soil. Check dates with the frost date lookup.
- Choose full sun. At least 6 hours of direct sun (NC State Extension); shaded plants make thin stalks.
- Prepare rich, well-drained soil. PlantVillage recommends working in 2 to 4 inches of compost and notes lemongrass grows best in well-draining, fertile loam. It likes steady moisture but not soggy ground; in heavy clay, plant in a raised bed or large container.
- Plant at the same depth it grew in the pot, and space divisions about 3 feet apart (UF/IFAS Extension Nassau County); PlantVillage gives 36 to 60 inches for home gardens. A single plant can form a clump several feet tall and wide in one warm season.
- Water deeply and regularly through summer, especially in heat. It is a tropical grass and grows fastest with consistent moisture.
- Feed through summer. PlantVillage notes lemongrass has a heavy nitrogen requirement during the growing season and recommends a balanced soluble fertilizer once a month for in-ground plants. UF/IFAS Nassau County suggests feeding container plants weekly with a half-strength balanced soluble fertilizer from June through September. Stop feeding as fall approaches.
Growing lemongrass in containers
Pots are the easiest way to grow lemongrass in cold climates, because you can carry the plant indoors in fall. Use a large container with drainage holes (bigger pots give more stalks) and a quality potting mix with compost. Container plants dry out and use up nutrients quickly, so water whenever the top inch is dry and feed more often than in-ground plants (weekly at half strength from June through September, per UF/IFAS Nassau County). Divide the clump when it fills the pot. For other herbs suited to pots, see best vegetables for containers.
How to harvest lemongrass
- Wait for thick stalks. Harvest stalks any time once they are at least ½ inch thick at the base (UF/IFAS Extension Nassau County; PlantVillage).
- Take outer stalks first. Cut, or twist and pull off, individual stalks at ground level from the outside of the clump. The center keeps producing.
- Wear gloves. The leaf edges are sharp enough to nick skin.
- Use the right part. Trim off the leafy tops; the tender, aromatic lower few inches of stalk is what goes into curries, soups and marinades. Peel away the tough outer layer, then bruise, slice or pound the core.
- Save the leaves for tea and broths; bruise or cut them to release scent.
- Store stalks in the refrigerator for short-term use, or freeze them whole or sliced for months.
In zones 3–7, do a large harvest just before the first fall frost, unless you plan to overwinter the plant.
Overwintering lemongrass in cold climates
North of zone 8 you have three options before frost. NC State Extension suggests overwintering lemongrass as a container plant and not letting it dry out, and UF/IFAS Extension Nassau County recommends saving a 6-inch section of the bulbous shoot base with roots attached before the first fall frost.
| Method | How | Best if |
|---|---|---|
| Keep it growing indoors | Before frost, dig a division (or bring in the pot), cut leaves back, pot it up, and keep it in a warm, bright, sunny spot (UF/IFAS). Do not let the mix dry out completely. | You have a bright south-facing window or grow light |
| Save the stalk base | After harvest, keep the bulbous shoot base with its roots and store it until spring, as PlantVillage describes for colder areas; then pot it up to regrow. | You lack bright window space |
| Restart from stalks | Let the plant die and root fresh grocery stalks, or a few saved stalks, in late winter. | You want the least effort |
Move overwintered plants back outdoors after the last frost, hardening them off over a week or so. The same dig-and-store approach used for other tender plants is in how to overwinter tender perennials.
Lemongrass and pets
The ASPCA lists lemon grass as toxic to dogs, cats and horses. It names essential oils and cyanogenic glycosides as the toxic principles, with stomach upset as the clinical sign in dogs and cats, and breathing difficulty and weakness (rarely death) in horses. Grow it where pets that graze on grass can't reach it, and contact a veterinarian or pet poison line if a pet eats a significant amount.
Problems
| Symptom | Likely cause | Fix |
|---|---|---|
| Thin, weak stalks | Too little sun, water or nitrogen | Move to full sun; water deeply; feed monthly in summer |
| No growth after planting out | Cold soil and cool nights | Wait until nights stay above about 50°F; best growth comes at 77–86°F (PlantVillage) |
| Light yellow spots on leaves, dark brown pustules underneath | Rust fungus (Puccinia nakanishikii) | Prune out affected leaves to allow healthy regrowth; avoid overhead watering (PlantVillage) |
| Brown leaf tips indoors | Dry indoor air or dry potting mix | Water more consistently; trim tips |
| Rotting base, yellow leaves in a pot | Waterlogged mix, especially in winter | Let mix dry between waterings; use a pot with drainage |
Common mistakes
| Mistake | Why it matters | Do this instead |
|---|---|---|
| Mistake | Why it matters | Do this instead |
| Planting out in early spring | Cold soil stalls growth for weeks | Wait until nights stay above about 50°F |
| Buying 'lemongrass seed' expecting the cooking type | UF/IFAS notes lemongrass is rarely grown from seed, and packets may hold another <em>Cymbopogon</em> species | Start from nursery plants, divisions or grocery stalks |
| Growing in part shade | Thin, weak stalks | Give it full sun |
| Leaving it in the ground in zones 3–7 | First hard frost kills the clump | Pot up a division before frost or harvest it all |
| Overwatering a dormant plant indoors | Crown rot | Water lightly while it rests |
Frequently asked
Is lemongrass a perennial?
It is a tender perennial. Lemongrass returns year after year where winters are frost-free or nearly so; NC State Extension lists USDA zones 8b–11. In colder zones it is grown as a summer annual or overwintered indoors.
Does lemongrass come back every year?
In warm climates, yes; the clump regrows each spring and keeps expanding. Where the ground freezes, the plant dies over winter unless you dig a division and keep it indoors.
How do you harvest lemongrass?
Cut or twist off the outer stalks at ground level once they are at least ½ inch thick, per UF/IFAS Extension, leaving the center to keep growing. Use the tender lower few inches of the stalk for cooking and the leaves for tea.
How tall does lemongrass grow?
NC State Extension lists 2 to 4 feet tall and 2 to 3 feet wide, and UF/IFAS notes it can reach about 6 feet tall in ideal warm, humid, well-watered conditions. Plants in pots or cooler summers stay smaller.
Can you grow lemongrass from store-bought stalks?
Often, yes. Choose fresh stalks with the base intact, stand them in a few inches of water in a bright window, change the water every few days, and pot them up once roots reach an inch or two.
Is lemongrass safe for dogs and cats?
The ASPCA lists lemon grass as toxic to dogs, cats and horses, citing essential oils and cyanogenic glycosides. It lists stomach upset as the sign in dogs and cats. Keep it out of reach of pets that chew grass.
Can you grow lemongrass from seed?
UF/IFAS Extension notes that lemongrass is rarely grown from seed. Nursery plants, divisions or rooted grocery stalks of Cymbopogon citratus give the classic cooking type faster, and seed sold simply as lemongrass may be another Cymbopogon species, so check the botanical name.
Sources
- Cymbopogon citratus (Lemongrass), NC State Extension Plant Toolbox
- Lemongrass, UF/IFAS Gardening Solutions
- Fact sheet: Lemongrass, UF/IFAS Extension Nassau County
- Toxic and Non-toxic Plants: Lemon Grass, ASPCA Animal Poison Control
- Lemon grass, PlantVillage, Penn State University