Lemongrass

Lemongrass is a true tropical grass, not a herb in the botanical sense at all, and it shows in how it grows: dense, clumping, upright blades that can reach four feet or more in a single warm season, with none of the frost tolerance most of the other plants in this reference have. Outside genuinely tropical and subtropical climates it's grown as an annual or brought indoors, most practically as a container plant that can be moved before frost.

Citral, Not Citrus

Lemongrass's lemon scent comes from citral, an aromatic compound also found in actual citrus peel but produced here by an entirely unrelated grass species - the plant has no relation to citrus fruit beyond sharing that one compound's scent profile. This is the same compound responsible for a good portion of true lemon's characteristic smell, which is why the two read as similar even though botanically they're nothing alike.

Only the Base of the Stalk Is Actually Used

In cooking, only the pale, tender lower few inches of the stalk - closest to the root, where the leaf sheaths are tightly wrapped and haven't toughened yet - is typically minced or pounded into a paste for dishes. The tough, fibrous upper leaves aren't discarded outright, though; they're commonly simmered whole for tea or broth, since the flavor infuses out even though the fiber itself stays too tough to chew.

Overwintering North of the Tropics

A lemongrass clump can be dug up and brought indoors before frost, kept in a cool, bright spot with reduced watering through winter, and replanted outside once the danger of frost has passed - a practical way to keep the same plant going year after year in a climate that would otherwise kill it outright each winter, rather than buying a new plant annually.

Harvesting Without Killing the Clump

Individual stalks are harvested by cutting or twisting the outermost, most mature stalks at the base while leaving the smaller, inner stalks to keep growing - the same clump-management logic used with rhubarb or chives, where taking everything at once sets the plant back far more than a rolling harvest of the oldest growth. A well-established clump can supply stalks continuously through a full warm season this way rather than being harvested once and left to regrow from nothing.

A Foundation Flavor, Not a Garnish

Lemongrass functions as a base aromatic in the cuisines that use it, closer in role to how onion or garlic anchors many Western dishes than to how a fresh herb like basil is used as a finishing touch - it's pounded into the paste base of Thai curries, simmered whole in Vietnamese pho broth for its aroma before being removed, and featured prominently in tom yum soup, where its citrus-forward sourness is a defining rather than incidental flavor.

Companions: A Traditional Pest-Masking Pairing With Tomatoes

Lemongrass near tomatoes follows the same traditional scent-masking logic common to most strongly aromatic companion herbs - plausible in principle, not tested with controlled trials for this specific pairing. Lemongrass's real, better-documented garden value is as a citronella-adjacent mosquito deterrent when planted near seating areas, a separate claim from anything about protecting neighboring vegetables.