Lemongrass: Tall Citrus-Scented Herb for Containers

Start by picturing a clump of narrow, blue-green blades that looks a bit like a shorter ornamental grass but smells like lemons when you brush past it. That is lemongrass, a tender perennial in the grass family grown as an herb.

Grow Cymbopogon citratus for its thick, pale lower stems and fibrous rhizomes that store energy. Those swollen bases are the edible part you see in grocery stores, while the leaves contribute fragrance to teas and infusions.

Expect clumps to reach 3-5 ft tall and about 2-3 ft wide in one warm season, similar in height to a medium daylily clump but more upright. In Zones 9-10, plants can act as short-lived perennials with fresh growth from the base each year.

Treat lemongrass like a frost-tender warm-season herb in cooler regions, the same way you handle basil and other tropical herbs in summer herb beds. In Zone 4-8, you either replant each year or pot it up and overwinter indoors.

Choose Cymbopogon citratus when your goal is cooking quality and strong citrus flavor. This is the common West Indian lemongrass used in Thai and Vietnamese dishes, and it is what most nurseries sell in herb sections.

Ask your nursery to confirm species, because citronella grass (Cymbopogon nardus or C. winterianus) looks very similar but is grown mainly for oil and mosquito products. It has coarser leaves and less desirable flavor in the kitchen.

Look for named selections only if you find them through specialty herb growers. Some offer strains selected for higher essential oil content or thicker stems, but for a home bed the generic labeled lemongrass is perfectly fine.

Plant lemongrass near other heat-loving herbs like oregano, sage, and rosemary so you can tune one watering pattern for that whole bed. You can group these with warm-season vegetables in a sunny kitchen garden without complicating care.

Put lemongrass where it gets 6-8+ hours of direct sun daily. Strong light builds thick stems and a high oil content, very similar to other sun lovers like lavender and rosemary that you might already grow in a front bed.

Watch leaf color to judge if light is right. Pale, floppy blades and weak stems usually mean the plant is stuck in bright shade or only brief morning sun, while deep green and upright growth signal enough direct light.

Shift containers a few feet if nearby shrubs like hydrangea or boxwood start casting afternoon shade as they leaf out. Even half a day of shadow can slow growth in short-season climates such as Zone 4-5 where every warm week counts.

Protect young transplants from sudden full-sun exposure by hardening them off over 7-10 days, especially if you started them indoors under lights. Follow the same gradual exposure steps you would use from a seedling hardening guide.

Keep lemongrass on the moist side, not soggy. Water when the top 1-2 inches of soil feel dry, similar to how you might treat mint in a large pot, but avoid the constantly wet conditions that invite rot.

Check moisture with your finger all the way to your second knuckle instead of following a strict calendar. In hot, windy weather you might water every 1-2 days in containers, while in cooler shoulder seasons beds may go 3-5 days between soakings.

Aim to water deeply so moisture reaches 6-8 inches down into the root zone, then let the surface dry slightly. This deep approach lines up with advice in deep versus frequent watering and encourages stronger roots.

Watch for curling or browning leaf tips as an early warning for underwatering, especially in smaller pots that heat up on patios. On the flip side, yellowing from the base and a sour smell in the soil point toward chronic overwatering or poor drainage.

Start lemongrass in a loose, fertile mix that drains well but never turns to dust. A blend of 40% compost, 40% good garden soil, and 20% coarse sand or perlite works well in beds and raised planters.

Aim for a slightly acidic to neutral pH around 6.0-7.0, similar to what tomato or pepper plants prefer in mixed kitchen beds. Heavy clay soil should be loosened at least 12 inches deep and amended generously with organic matter.

Grow lemongrass in containers at least 14-18 inches wide and deep so the rhizomes and roots have space. Use a quality potting mix rather than straight garden soil, just like you would for indoor herb containers.

Check that any pot has large drainage holes and that they are not blocked by saucers or decks. Poor drainage is the soil problem that kills lemongrass fastest because waterlogged roots rot in warm weather long before leaves show stress.

Starting from seed frustrates a lot of gardeners, because germination is slow and seedlings grow weak. Division of mature clumps is faster, more reliable, and gives you harvestable lemongrass in the same season.

Lifting big clumps all at once can shock the plant. Instead, slice off a section from the edge with a sharp spade, keeping a chunk of rhizomes and several healthy stalks together.

Planting straight into cold ground in Zone 4 or Zone 5 often stalls new divisions. Pot them up first, then shift them outside once you have hardened them off using the steps in hardening seedlings outdoors.

Assuming the strong citrus scent keeps every pest away is the first mistake. Lemongrass dodges many bugs, but stressed plants still attract sap suckers and root problems.

Ignoring sticky leaves and speckled blades lets small insects multiply quietly. Check the foliage while you weed nearby herbs like basil or woody rosemary, so pest issues never sneak up on you.

Treating lemongrass the same in Zone 4 as in Zone 10 is why many clumps disappear over winter. In colder areas you grow it like a tender annual, while warm zones can keep it going for years.

Leaving plants outside for a surprise frost is the fastest way to black, mushy leaves. Move container plants under cover when nights dip near 35°F, similar to how you baby a young patio lemon tree.

Letting kids or pets chew raw stalks is not a great idea, even for "edible" herbs. The leaves are tough and fibrous, and the strong oils can upset sensitive stomachs.

Treating lemongrass like soft lawn grass can also cause mouth cuts. The narrow blades have sharp edges, a bit like ornamental grasses, and can irritate lips or gums if animals nibble them often.

Planting it from treated nursery stock and then assuming sprays have vanished can catch food gardeners off guard. Always check labels and give at least the recommended pre harvest interval before using stalks in the kitchen.

Letting clumps escape into nearby wild wet areas is sometimes a concern in frost free regions. In most Zone 4-8 yards winter cold keeps it in check, but warm Zone 10 gardens should avoid tossing rooted pieces into natural waterways.