A small culinary herb native to Southeast Asia, Persicaria odorata, recently reclassified from Polygonum odoratum. Also known as hot mint, laksa leaf (duan laksa), rau ram, Cambodian mint and Vietnamese coriander. The popular mint name has stuck in the west, even though it is not related to the mint group of herbs, but is more closely related to buckwheat and rhubarb.
It is a small perennial growing to a height of 50 cm (17 in). The leaves have a slender pointy appearance, around 5 cm long and are deep, dark green in colour.
The flavour of the herb is strongly pungent, with powerful citrus and pepper overtones. It is close to ubiquitous as a salad ingredient in Vietnam and diners ordering pho soup will be offered a small side plate containing bean sprouts, Thai basil and Vietnamese mint to add according to their discretion.
Elsewhere in Asia, it will be found cooked, rather than raw. It is so closely associated with Singaporean and Malay spicy soup, laksa, that it provides one of the herbs common names. It is known as duan laksa in Malaysia and Singapore, rua ram in Vietnam and phak phai in Thailand.
As with almost all aromatic Asian herbs, it loses its vitality when dried, but if you manage to find the herb fresh, it is not too hard to propagate for planting. Simply place the stems in some water and wait for roots to sprout. Plant in a sunny spot and indulge its thirsty nature.