Spartium junceum (Genista juncea), known as Spanish Broom or Weaver's Broom, is a perennial, leguminous shrub native to the Mediterranean region in southern Europe, southwest Asia and northwest Africa, where it is found in sunny sites, usually on dry, sandy soils. It is the sole species in the genus Spartium, but is closely related to the other brooms in the genera Cytisus and Genista.
The plant typically grows to 2 to 4 meters tall, with main stems up to 5 centimeters thick. It has thick, somewhat succulent grey-green rush-like shoots with very sparse small deciduous leaves 1 to 3 centimeters long and up to 4 millimeters broad. The leaves are of little importance to the plant, with much of the photosynthesis occurring in the green shoots (a water-conserving strategy in its dry climate). The leaves fall away early. In late spring and summer shoots are covered in profuse fragrant yellow flowers 1 to 2 centimeters across. In late summer, the legumes (seed pods) mature black and reach up to 8 or 10 centimeters long. They burst open, often with an audible crack, spreading seed from the parent plant.
Spartium junceum has been widely introduced into other areas, and the plant is used as an ornamental plant in gardens and in landscape plantings. In Bolivia and Peru, the plant is known as retama, and has become very well established in some areas. It is one of the most common ornamental plants, often seen growing along sidewalks in La Paz.
The plant is also used as a flavoring, and for its essential oil, known as Genet Absolute. Its fibers have been used for cloth and it produces a yellow dye.