About

Salsola tragus, often known by its synonym Kali tragus, is a species of flowering plant in the family Amaranthaceae. It is known by various common names such as prickly Russian thistle, windwitch, or common saltwort. It is widely known simply as tumbleweed because, in many regions of the United States, it is the most common and most conspicuous plant species that produces tumbleweeds. Informally, it may be known as Kali or Salsola: the latter being its restored genus, containing 54 other species, into which the obsolete genus Kali has been subsumed.

For a brief period during its youth, it may be grazed, but afterward it becomes too spiny and woody to be edible for most wildlife and livestock (unless processed first). Mature specimens are often more than a meter in diameter. As its fruits mature, the diaspore of the plant dies, dries, hardens, and detaches from its root.

Where it grows

Salsola tragus is a ruderal annual forb. It germinates rapidly even with very little moisture in arid conditions. When young, it may be grazed freely, but that phase lasts for only a brief period, and generally at a time when other forage is relatively plentiful. After this, it becomes a weed in most contexts. One reason is that as they mature, most varieties become too spiny and woody for most stock to browse. Moreover, older foliage develops higher levels of oxalates, bitter tannins, and alkaloids, making it unpalatable. As its fruits mature, the plant dies, dries, and becomes hard and brittle. In this state, it is likely to detach from its root and become a tumbleweed. As tumbleweeds go, it is very large, often a metre or more in diameter, spiny, largely inedible to most livestock if unprocessed, and a fire hazard. However, in regions where there is plentiful winter rain, the moisture softens both the twigs and the spines, after which hardy breeds of livestock and some wildlife species once again will eat it.

Other Salsola plants

Russian thistle · Russian Thistle · Saltwort