The “mustard tree” is often mistakenly associated with the culinary condiment. However, this plant is not the source of the mustard seeds used in kitchens. This article explores its true identity, natural habitats, distinctive characteristics, and traditional uses.
Identifying the Mustard Tree
The plant known as the “mustard tree” is scientifically classified as Salvadora persica. It belongs to the Salvadoraceae family. This species is typically a small tree or shrub, often reaching heights of 6–7 meters (20–23 feet). It possesses a crooked trunk and scabrous, cracked, whitish bark. Its overall form can be spreading with profusely branched, drooping extremities.
Where Mustard Trees Grow
Salvadora persica is indigenous to arid and semi-arid regions across the Middle East, North Africa, and extending eastward into India. It thrives in environments where groundwater is accessible, commonly found along desert floodplains, riverbanks, and grassy savannahs. This plant exhibits a notable tolerance for salty soils and can endure conditions with as little as 200 millimeters of annual rainfall, making it well-suited for harsh climates.
Key Features and Lifecycle
Salvadora persica is an evergreen plant. Its leaves are dark green, round, and fleshy, often described as somewhat brittle or leathery, and arranged in opposite pairs. These leaves measure about 3–7 centimeters long. The plant produces small, fragrant flowers that are typically greenish to yellowish and appear in loose, slender-branched clusters.
Following flowering, the mustard tree develops small, spherical, fleshy, berry-like fruits. These drupes measure approximately 5-10 millimeters in diameter and change color from pink to scarlet or red when ripe. They are edible, with a juicy, pungent, and sometimes peppery taste. The plant propagates through seeds or cuttings.
Connecting to Culinary Mustard and Beyond
Despite its common name, Salvadora persica is not the source of culinary mustard. Commercial mustard seeds are derived from species within the Brassica genus, such as Sinapis alba, Brassica nigra, and Brassica juncea. These plants are distinct from Salvadora persica and belong to the Brassicaceae family.
Salvadora persica has a history of diverse applications. Its twigs and roots, known as “miswak” or “siwak,” have been traditionally used for centuries as natural toothbrushes across the Arabian Peninsula, Africa, and India. These are valued for their mechanical cleaning action and compounds that support oral hygiene, including antibacterial properties. Various parts of the plant, including leaves, bark, and fruits, have also been used in traditional medicine for digestive issues, respiratory problems, and skin conditions. The plant also serves as a source of fodder for animals and its wood can be used for charcoal.