Tragacanth, Gum tragacanth milkvetch

Astragalus gummifer

Physical Characteristics

Astragalus gummifer is an evergreen Shrub growing to 0.3 m (1ft) by 0.3 m (1ft in) at a medium rate. See above for USDA hardiness. It is hardy to UK zone 8. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees, Lepidoptera (Moths & Butterflies). The plant is self-fertile. It can fix Nitrogen. It is noted for attracting wildlife. Suitable for: light (sandy) and medium (loamy) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very acid soils. It cannot grow in the shade. It prefers dry soil.

Distribution

W. Asia - Iraq, Kurdistan

Habitats

Cultivated Beds;

Edible Uses

Edible Parts: Edible Uses: Gum Gum A source of a high quality gum tragacanth - used as a thickener in confections, salad dressings, sauces etc[2, 4, 57, 64, 105, 114]. It is an approved additive to food and has the E number E413[238]. Some of the gum exudes naturally from the root and from damaged stems[171], more can be obtained by incision of the stem about 5cm below ground level[64].

Medicinal Uses

Adaptogen Antitumor Demulcent The gum obtained from the root and stem is demulcent, though it is not often used internally because it is not completely soluble[4]. This gum has recently been shown to stimulate the immune system and to suppress tumours[238]. The gum has long been employed externally as a dressing for burns and is also used in lozenges in order to bind the ingredients and impart consistency to the product[4].

Known Hazards

Many members of this genus contain toxic glycosides[65]. All species with edible seedpods can be distinguished by their fleshy round or oval seedpod that looks somewhat like a greengage[85]. A number of species can also accumulate toxic levels of selenium when grown in soils that are relatively rich in that element[65].