Is Lemongrass a Grass: Botanical Family and Key Differences Explained

Lemongrass belongs to the Cymbopogon genus, part of the broader Poaceae family's subfamily Andropogoneae, which includes other aromatic plants like citronella. 🌿 Unlike true grasses, lemongrass produces long, hollow stalks with linear leaves arranged in a fan pattern—key traits that set it apart from lawn grasses like Bermuda or fescue.

Its rhizomatous growth habit also differs from grass tillers, making it more herb-like in cultivation.

This tropical herb thrives in warm climates and requires consistent moisture, unlike many ornamental grasses that tolerate drought. The confusion often stems from its grass-like appearance, but botanists classify it separately due to its unique leaf anatomy and reproductive structures.

For gardeners, understanding this distinction helps in choosing the right companion plants and care routines.

Botanical classification: why lemongrass isn’t a grass

Lemongrass belongs to the Cymbopogon genus within the Poaceae family's Andropogoneae subfamily, but its classification as a "grass" is botanically inaccurate.

True grasses like wheat or bamboo have parallel leaf veins and produce seeds in clusters called spikelets, while lemongrass features rolled, linear leaves with a central vein and aromatic oils in specialized cells called schizogenous glands.

These glands release citral and geraniol compounds, giving lemongrass its signature citrusy aroma that true grasses lack entirely.

The confusion arises from its grass-like appearance—lemongrass grows in clumps via underground rhizomes (horizontal stems), similar to how some ornamental grasses spread. However, its reproductive structures differ: lemongrass produces panicles (branched clusters) of tiny flowers, whereas true grasses form spikelets along a single stem.

This floral distinction is why botanists categorize it separately, despite superficial similarities to grasses like Miscanthus or Pennisetum.

For gardeners, this matters because lemongrass thrives in tropical conditions (70-85°F) with consistent moisture, unlike drought-tolerant ornamental grasses. Its hollow, woody stalks reach 3-5 feet tall, while true grasses typically remain 1-3 feet and lack the same aromatic compounds.

The leaf arrangement—alternate and fan-like—further separates it from grasses, which have opposite or whorled leaf patterns.

Here’s a quick comparison to clarify:

• Leaf Structure: Lemongrass has rolled, linear leaves with a single central vein; true grasses have flat blades with parallel veins.
• Growth Habit: Lemongrass spreads via rhizomes; grasses spread via tillers (above-ground shoots).
• Aromatic Compounds: Lemongrass contains citral and geraniol; grasses lack these volatile oils.
• Flower Type: Lemongrass produces panicles; grasses form spikelets.

The Cymbopogon genus includes over 55 species, with Cymbopogon citratus (West Indian lemongrass) being the most common. Its aromatic oils are concentrated in the lower leaf stalks, which is why chefs and herbalists focus on the bottom 6-8 inches of the stalk for maximum flavor.

This specialization is absent in true grasses, which lack such concentrated aromatic properties.

Understanding this distinction helps avoid mislabeling in gardens and kitchens. For example, planting lemongrass near true grasses like Bermuda won’t yield the same benefits—lemongrass needs rich, well-draining soil and partial shade in hot climates, while grasses thrive in full sun with sandy soil.

The botanical differences extend to pest resistance too: lemongrass repels mosquitoes due to its oils, while grasses offer no such protection. 🌿

Growing lemongrass: cultivation tips for home gardens

Start with fresh stalks from a grocery store or nursery—they're easier to root than dried bundles.

Cut the bottom 4-6 inches of the stalk, remove any lower leaves, and place it in a glass of water, ensuring the nodes (where leaves grow) are submerged. 🌱 Change the water every 2-3 days, and in about 2 weeks, you'll see roots forming.

Once roots reach 2-3 inches, transplant into pots with well-draining soil or directly into your garden if temperatures stay above 60°F.

Lemongrass thrives in partial shade (4-6 hours of sunlight daily) but can tolerate full sun in cooler climates. Use a mix of potting soil and perlite for containers to prevent root rot, which is a common issue with this tropical herb.

Keep the soil consistently moist—never soggy—by watering when the top inch feels dry. In hot climates, mulch around the base to retain moisture and protect roots from extreme heat.

One mistake beginners make is harvesting too aggressively. Wait until your lemongrass reaches 12-18 inches tall before cutting stalks for use. Always cut from the outer stalks first to encourage new growth from the center.

If you're growing in pots, rotate them occasionally to ensure even sunlight exposure, which prevents lopsided growth. In colder months, bring potted lemongrass indoors near a sunny window or under grow lights.

For propagation, divide mature clumps in spring by carefully separating the rhizomes with a clean knife. Each section should have at least 3-4 stalks and some roots. Replant immediately in fresh soil and water thoroughly. 🌿 This method ensures you get multiple plants from one established clump.

If you're growing lemongrass in containers, choose pots at least 12 inches wide to accommodate its spreading rhizomes—smaller pots will restrict growth and lead to overcrowding.

Watch for pests like aphids or spider mites, which can attack stressed plants. A quick spray of soapy water (1 tablespoon mild dish soap per quart of water) usually resolves minor infestations. For larger gardens, interplant lemongrass with herbs like basil or cilantro—their strong scents naturally deter pests.

With proper care, your lemongrass can live for years, providing a fresh supply of stalks for cooking and herbal remedies.