Vietnamese Coriander, Vietnamese Mint, Rau Ram, Laksa Leaf

Species

Persicaria odorata

Leaf Type

Simple, evergreen in tropical climates (perennial herb)

Family

Polygonaceae (Buckwheat or Knotweed family)

Shape

Lanceolate, tapering to a sharp point

Size

Approximately 3-5 inches (8-12 cm) long and 0.5-1 inch (1.5-3 cm) wide, which is standard for mature leaves in cultivated pots.

Margin

Entire (smooth), though sometimes slightly undulating

Arrangement

Alternate; the leaves emerge from swollen nodes surrounded by a thin, papery sheath called an ocrea, typical of the Polygonaceae family.

Rarity

Common (regularly encountered in Asian markets and specialty nurseries).

Color & Pattern

Bright green upper surface featuring a distinctive dark purple or brownish-black chevron (V-shaped or crescent) mark in the center. The underside is often a lighter, paler green.

Venation Pattern

Pinnate with a prominent light green midrib and faint secondary veins extending toward the margin.

Texture & Surface

Smooth (glabrous) and slightly waxy on the upper surface; thin and flexible (papery) texture.

Description

A spreading perennial herb that grows in lush, low-lying clumps. The stems are somewhat decumbent and take root at the nodes when in contact with soil. It produces small, inconspicuous pink flowers in spikes, though it rarely blooms outside its native tropical range. The plant is best known for its uniquely pungent, lemony, and peppery aroma when brushed or crushed.

Key Features

The most diagnostic feature is the dark 'thumbprint' or smudged chevron pattern on the center of the lanceolate leaf, combined with the characteristic 'papery sheath' (ocrea) at the base of the petiole.

Habitat

Tropical and subtropical wetlands; prefers moist to wet soil, high humidity, and partial shade. Commonly grown in containers in temperate zones.

Geographic Range

Native to Southeast Asia (Vietnam, Laos, Cambodia, Thailand). Introduced and naturalized in various tropical regions; commonly cultivated globally in herb gardens.

Condition Notes

The leaf appears to be in Good to Excellent health. There is a small white blemish on the mid-leaf, likely a minor mechanical injury or hard water spot, but no signs of significant pests or disease are present.

Interesting Facts

Despite the common name 'Vietnamese Mint,' it is not a member of the mint family (Lamiaceae). In Buddhist tradition in some regions, it is reportedly consumed to help suppress libido, aiding in the celibate lifestyle of monks.

Medicinal & Uses

Widely used in Southeast Asian cuisine, particularly in Laksa soups and summer rolls. Medicinally, it is used in traditional folk medicine for indigestion and skin inflammatory conditions. The essential oil has antimicrobial properties.

Ecological Role

Provides ground cover in riparian zones and serves as a host for various small insects in its native range. It is generally not considered invasive in temperate climates as it is frost-sensitive.

Similar Species

Polygonum persicaria (Lady's Thumb) - very similar blotch, but less aromatic and typically considered a weed. Persicaria hydropiper (Water Pepper) - lacks the distinct sweet-citrus fragrance and has a much more acrid, 'burning' taste.

Foraging Tips

Look for this in damp garden beds or near water features in warmer zones. Rub a leaf between your fingers: it should smell strongly of lemon and coriander with a peppery kick. This scent is the best field identification indicator.

Toxicity Warning

Non-toxic to humans and generally safe for culinary use. However, some sources suggest large quantities should be avoided by pregnant women due to traditional uses as an emmenagogue.

Identified on 7/18/2026