Astragalus is a perennial herb from the legume family of plants that is cultivated for it's medicinal root. In traditional chinese medicine, Astragalus (aka Huang Chi or Huáng Qí) is a fundamental herb and is used for strengthening the immune system, increasing stamina and internal warmth. The plant contains many constituents including astragalosides, and other immuno-stimulant polysaccharides, beta-sitosterol, flavonoids, and trace minerals, especially selenium.
When planting Astragalus make sure you give plenty of space between plants. Astragalus prefers sunny locations, and well drained, sandy soils. Realize that this soil composition will result in the plant requiring frequent watering. The root is best harvested for medicinal use after 3 years of growth, as this will give the plant plenty of time to increase the amount of constituent healing chemicals within it.