Salsola tragus

It has a high tolerance of salinity and can successfully compete with many native plants in certain environments, such as along sea beaches and especially in grassland, desert, or semiarid regions.

Native to Eurasia, Salsola tragus has proven to be highly invasive as an introduced species and rapidly became a common ruderal weed of disturbed habitats throughout the world.

[2] The tumbleweed's tumbling is known to damage non-native plants and environments and its highly flammable nature also sometimes helps wildfires spread, especially during windy conditions.

Recent studies show that the population that once was assigned to Salsola tragus includes three or more morphologically similar species that differ in flower size and shape.

[9] Salsola tragus has proven to be highly invasive as an introduced species and rapidly became a common ruderal weed of disturbed habitats in many regions of North America, particularly in the Midwest.

[10] It now occupies a wide variety of habitat types in those regions and often is the first or even the only colonizer in conditions where no local species can compete successfully.

Because of its preference for sand and its tolerance of salinity, it commonly grows along sea beaches as well as in disturbed grassland and desert communities, especially in semiarid regions.

[15] 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.

[11] Salsola tragus has acquired a bad reputation for its spininess, its woodiness when mature, and its general ecological competitiveness, augmented by its tumbleweed nature, which enables it to spread rapidly over open ground.

Prince Gallitzin reported that on the journey out of his native Russia he passed through southwest Siberia and found the Imperial government's irrigation project abandoned and the farms deserted, on account of K. tragus.

[3] During the past century or more, the majority of the publications that dealt with the topic have discussed its pernicious nature, the increasing threats that the species poses, and how to combat its invasiveness; they largely have ignored its other attributes.

[11] Apart from its value to domestic cattle and sheep in some regions, Kali tragus is a source of food and shelter for several species of wild life.

[11] Some livestock species such as camels and some breeds of stock that are adapted to semi-desert conditions will brave the spines when forage becomes scarce.

[11] Oxalic acid occurs in a wide range of plants including S. tragus as an adaptation to alkaline, relatively drier soils rich in calcite, gypsum, alumina, and/or other metal ions.

Oxalic acid forms highly insoluble salts with calcium, aluminum, chromium, copper, lead, and many other transition metals.

Salsola tragus and many related species, including some that are widely regarded as invasive weeds in other countries, are valued in their regions of origin.

In Uzbekistan, for example, stems, fruits, and leaves are nutritious year-round camel feed; sheep and goats prefer it in summer, but also to some extent in autumn and winter.

In those regions annual Salsola species are known as "solyanki"; they are important as drought- and salt-tolerant forage and form a dominant group in the flora and vegetation of the most challenging environments.

[16] Although Salsola still has not won much recognition in contemporary first-world livestock nutrition, this might reflect short memories rather than shortage of evidence for its merits; during the Dust Bowl era, it was credited with having rescued beef cattle husbandry in North America.

Often its presence is beneficial, especially when the original topsoil still is present; the species happens not to be host to any mycorrhizal fungi, whereas many or most common plants in fact are so adapted.

[11] However, it is important not to regard the ecological interrelationships too simplistically; in some cases the presence of the healthy weed plants on a harsh site without mycorrhizae actually seems to facilitate the succession of grass better than where a mycorrhizal inoculum had reduced the population of the Salsola.

A good example was in controlling troublesome Kali on Bighorn Sheep Winter Ranges in Jasper National Park by proper management of grazing intensity.

Because such soil situations as mine dumps tend to be extreme examples of disturbed sites, and often are of fine texture, Kali species show promise for certain classes of such work.

Simply by growing there in high density they can play a valuable role in phytostabilization by reducing wind erosion and similar processes that promote the spread of pollution.

[19] However, a plant that has absorbed some of the levels of toxic substances (e.g., arsenic, lead, or cadmium) that the Kali species can accumulate [19] probably would not be suitable for food or fodder.

In particular, it increases total nitrogen content but reduces some (possibly harmless) levels of potentially toxic substances such as soluble oxalate and nitrate.

[20] Secondly, in a season in which the Kali growth has been heavy, high winds often accumulate shocking tangles of the tumbleweeds, covering entire buildings or trapping vehicles so completely as to prevent unaided escape, particularly in the event that the dry material ignites.

In wildfire conditions in open country, strong winds often blow burning tumbleweeds across firebreaks, frustrating standard fire control measures.

When the burning weeds are stopped by buildings or stacks, they ignite such objects more effectively than any other tumbleweed on the open plains, being compact and woody at maturity, as well as highly flammable.

[27] In its freshly sprouted form, before it has developed spines or unpleasantly tough fibres, Kali tragus has been recommended as a salad, stir-fry, or potherb for human consumption.

Kali tragus , the Russian thistle
Leaves of a mature plant coming into flower, each leaf with one flower and two bracts in its axil
Largely ripe fruit of Kali tragus .
Kali tragus rolling in the wind in Hockenheim , Germany (November 2015).
Immature specimen of Kali tragus , with juvenile foliage. Young plants are edible.
Kali tragus is an unusually large species of tumbleweed. This specimen – although still green – is above average, but not exceptional. (August 2002)
Farmer in Haskell County , Kansas burning tumbleweeds in a roadside ditch (April 1941).
A counterproductive attempt at rangeland restoration in Idaho . After a wildfire , only Kali tragus grew in the arid, saline clay soil, providing minimal forage for livestock and wildlife.
Kali tragus caught against a fence in Omaopio , on the Hawaiian Island of Maui (December 2000).