Gardener's Path

Thai basil is known by the scientific name O. basilicum var. thyrsiflora and is a cultivar of sweet basil. The herb is native to South-East Asia and has been selectively bred and grown for its distinctive flavour profile.

Thai basil is called káu-chàn-thah in Taiwan and is known as húng quế (cinnamon basil) in Vietnam, but the name can also refer to a separate type of cultivar.

Thai basil is believed to have first been cultivated in India or Asia before it spread to parts of the Mediterranean via spice routes linking eastern and western parts of the globe. It has been grown and consumed for more than 5,000 years.

Today, the herb is commonly used in Thai, Vietnamese, Laotian and Cambodian cookery. It is one of three types of basil used in Thai cuisine alongside holy basil and lemon basil.

Growth and harvest
Thai basil is best grown in warm, tropical climates that have no frost. It is a tender and compact herb with smaller foliage than sweet basil. Although Thai basil is technically considered a perennial plant, it is usually grown as an annual and has a lifespan of up to two years.

For optimum growth, Thai basil requires enriched soil with compost and should be planted in an area that gets full sun. Regular watering of the soil is required, especially during hot, dry weather, and mulch should be added to reduce the amount of water evaporation.

Leaves should be harvested above the node by hand or with scissors; care should be taken to ensure the leaves aren’t damaged as they bruise easily.

Flavour profile and appearance
The plants have long square purple stems that grow upright with matching purple flowers heads that can grow up to 4.5cm. The leaves reach between 2.5-5cm in size and are deep vibrant green in colour with serrated, jagged edges.

Thai basil can be eaten fresh or cooked and has an anise or liquorice flavour that can also be a little spicy. The herb has the ability to withstand higher cooking temperatures than sweet basil, which is why it is commonly used in stir fries and other wok dishes.

Culinary applications
Thai basil is a frequent addition to red and green curries in Thailand and is an essential ingredient in drunken noodles. In Vietnamese cooking, the herb is a topping for soup noodles such as pho and bún bò Huế as well as bánh xèo. It is also the hero ingredient in Taiwanese chicken dish san bei ji (three cup chicken).