Vietnamese Coriander / Laksa Leaf (Rau Răm, Daun Kesum)
What it is
A single species, Persicaria odorata (formerly Polygonum odoratum) — a low, spreading, knotweed-family herb with narrow, pointed leaves often marked by a dark chevron. One of the most important clarifications in this category: "Vietnamese coriander / rau răm," "Vietnamese mint," "laksa leaf," and "daun kesum" are all the same plant. It is neither a true coriander nor a true mint; the names reflect the cuisines that adopted it (Vietnamese vs. Malaysian/Singaporean), not different herbs.
How it's made
A tender perennial that roots readily from cuttings and thrives in warm, wet conditions; it is grown in home gardens and pots across Southeast Asia and harvested as fresh sprigs. It does not dry — the aroma vanishes entirely — so it is strictly a fresh, often live-plant, herb.
Flavor profile
Peppery, hot, and citrus-coriander-like with a soapy-green edge and a distinct lingering pungency and bitterness on the finish. Sharper and more biting than cilantro, with real heat — closer to a cross between cilantro, mint, and black pepper. Aromatic and assertive.
Culinary uses
Always raw or added at the very end. In Vietnam, rau răm is a centerpiece of the fresh herb plate served alongside noodle dishes, a classic partner to hột vịt lộn (balut) and gỏi (salads), and a flavor in fermented and fresh preparations. In Malaysia and Singapore, the same leaf — daun kesum — is the indispensable aromatic of laksa, finely shredded into and over the spicy coconut or assam noodle soup; the dish is so identified with it that the herb's English name became "laksa leaf." No dried form exists worth using; cilantro plus a little mint and pepper gestures at it but misses the specific pungent heat. Its absence is immediately obvious in a real laksa.
Regional variations
The plant is one species, but its culinary identity splits sharply: rau răm in Vietnamese herb-plate culture (raw, abundant, paired with rich and fermented foods) versus daun kesum / laksa leaf in Peranakan and Malay cooking (shredded into laksa and curries). Selection and intensity vary slightly with growing conditions, but the divide is cultural, not botanical.
Cultural & historical context
Native to Southeast Asia. In Vietnam, rau răm carries folk associations with cooling the libido and is traditionally eaten by monks; it is woven into the deep Vietnamese culture of the đĩa rau sống (raw herb plate), where a meal is incomplete without a heap of fresh herbs chosen leaf by leaf. Its journey into Nyonya (Peranakan) cooking as laksa leaf tracks the Chinese-Malay culinary fusion of the Straits Settlements. The four-names-one-plant tangle is a perfect emblem of how the same herb becomes a different cultural object in each cuisine that claims it.
Reference notes
Suggested slug: `rau-ram-laksa-leaf`. Tags: `herb`, `fresh-leaf`, `knotweed-family`, `use-raw`, `one-plant-many-names`, `no-dried-form`. Related ingredients: laksa paste, balut, rice noodles, coconut milk, cilantro (contrast). Related cuisines: Vietnamese, Malaysian, Singaporean (Peranakan). Suggested Cuisinopedia links: Laksa, Vietnamese Herb Plate, Cilantro, Culantro. Critical: index all four names (rau răm, Vietnamese mint, laksa leaf, daun kesum) to one entry and state explicitly they are the same species — this is a top "teach something" payoff.