Lemongrass: Tall Citrus-Scented Herb for Containers

Lemongrass grows as a warm-season clump of narrow, blue-green blades that smell like lemons when brushed or cut. It behaves more like a tender ornamental grass with edible stem bases than a soft leaf 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 regrow from the base, while in Zone 4-8, treat lemongrass like basil and other tropical herbs in summer herb beds, then replant or overwinter a pot before frost.

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.

For small patios, buy the fattest starter plant you can find instead of chasing named cultivars.

A single strong clump fills a pot quickly, while several skinny divisions in one container usually crowd each other before they produce thick kitchen stalks.

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 for hardening seedlings outdoors.

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 if nearby hydrangea, boxwood, or a porch rail starts cutting the day short, since even half a day of shade slows thick-stem growth in Zone 4-5 summers.

Harden indoor-started plants over 7-10 days with the same gradual exposure used in a seedling hardening guide.

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.

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.

The watering target changes once the clump fills its pot. A root-bound lemongrass plant can look thirsty every afternoon even when you watered that morning, so step up container size before you start watering twice a day.

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.

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.

Lemongrass is edible for people in normal kitchen amounts, but the leaves are tough, fibrous, and sharp-edged.

Do not treat it like soft lawn grass for kids or pets, since chewing raw blades can irritate mouths and upset sensitive stomachs.

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.