Russian Thistle-Goosefoot Family

 

Tumbleweed

               

Salsola iberica

 

 

Characteristics.  This weed was introduced from Russian in the late 1800s and has become one of the more important weed pests in the drier areas of North America.  It is especially common along roadsides, wastelands, overgrazed rangelands and drier cultivated agricultural fields.  It requires very little rainfall for seed germination and grows to maturity in the driest of situations.  Once mature the ball-shaped plants break off at the stem base and spread seed as the plant rolls with the wind.

Identifying Characteristics.  Mature plants are round in outline, considerably branched, ½ to 3 feet tall with red to purple striped stems.  The leaves in seedling plants are long, fleshy and soft.  Mature leaves are alternate, short, scale-like with a terminal spine.  Flowers are inconspicuous, green and located in upper leaf axils.  There is a similar species, barbwire Russian thistle that is similar in appearance by is typically more coarse and robust with stronger spines on the leaves.  Identification

Inconspicuous flowers are borne in axils of the upper leaves.  Each flower is accompanied by a pair of spiny, floral bracts. Seeds are round, black, smooth and shiny. Stems are red or purpled striped. The root system consists of a taproot that can grow 3 feet or more in depth with extensive lateral roots

Seedling:  Seedling plants have long, fleshy leaves. 

 

It is well adapted to cultivated dryland agriculture, but is also found on disturbed rangeland, and wasteland.   Russian thistle colonizes barren desert areas that cannot support other flora, and invades many different disturbed plant communities.  Since its introduction it has become one of the most common and troublesome weeds in the drier regions of the United States.  Russian thistle occurs in many communities.  It is most common along disturbed grassland and desert communities.  In disturbed big sagebrush communities, Russian thistle dominated for the first two years.  After this time plants became overcrowded and stunted, and were replaced by mustards.

    

 In spring, Russian thistle seeds will germinate at virtually any conceivable seedbed temperature.  Plants typically flower from July through October.  Seeds mature during August through November. Russian thistle seedlings are poor competitors, and do not establish well in crowded communities. Reproduces is by seeds. One plant can produce up to about 250,000 seeds.  Seeds remain viable less than a year. After seeds mature in the fall the plant stem separates from the root.  The plant is then blown by wind.  Seeds, held in the leaf axils, fall to the ground as the plant tumbles.

 

 

 

 

 

Genus Salsola. Salsola is a genus of herbs, subshrubs, shrubs, and small trees in the family Chenopodiaceae, native to Africa, Asia, and Europe. Plants in this genus typically grow on flat, often dry and/or somewhat saline soils, with some species in salt marshes. A few species are tumbleweeds. Recent genetic studies have however shown that the genus as traditionally circumscribed is paraphyletic, and many species are likely to be transferred to other genera in the future.

Common names of various members of this genus include tumbleweed, for its wind-blown seed dispersal habit; saltwort , for its salt tolerance; and Tartar thistle and Russian thistle for its origins, although it is not a thistle.

The leaves and shoots of many species are edible, especially when young and tender, and some are grown as vegetables, often used for salads, sushi, or as a garnish. The most commonly eaten European species is Salsola soda known in Italy as Barba di Frate or Agretti. In Japan, S. komarovii is a crop of moderate importance, known locally as okahijiki (literally "land hijiki").

Uses. The seeds are also edible, although difficult to collect in quantity, and are sometimes ground into flour. Salsola species are used as food plants by the larvae of some Lepidoptera species including The Nutmeg and the Coleophora case-bearers C. klimeschiella, C. parthenica, C. poeciliella (recorded on S. oppositifolia) and C. salsolella (feeds exclusively on S. vermiculata).

Several Salsola species, most notably the central Asian S. tragus, are invasive species outside their native range. They have encroached into parts of North America, where they are listed as noxious weeds by the U.S. Department of Agriculture. The salt-tolerant genus was first reported in the United States around 1877 in Bon Homme County, South Dakota, apparently transported as a stowaway in Flax seed exported by Ukrainianfarmers. South Dakota proved too harsh and dry for growing flax, however, and by 1900 Salsola had colonized as far west as the Pacific Coast. It was also actively introduced by the U.S.D.A. as experimental food for cattle that could be grown in hard times during droughts. Palatability of the young shoots is considered to be fair. Cattle, sheep, and horses eat it if nothing better is available. Small rodents and Pronghorn also graze on the young shoots. Salsola thrives wherever land use has disturbed the soil. It can be seen in Death Valley, California and in Colorado at elevations of 8500 feet (2600 m).

Several annual species form tumbleweeds: after the plant dries it breaks away from its taproot and is driven by the wind as a light, rolling mass, scattering seeds far and wide. The seeds are produced in large numbers and do not have a protective coating or food reserves for the coiled plant embryos. The deep, ineradicable taproot remains in the ground and survives to grow again the following season.  Salsola species with this habit include Salsola iberica and Salsola tragus.

Salsola tragus has naturalized to the point where it is regarded by many American people as native, changing the North American Great Plains plant community forever. It is controlled with mass applications of herbicides. Tumbleweeds of this species are such a common symbol in Westerns, where they are used to indicate an abandoned area, that they are generally associated with the American Old West and Western films, despite the species' Ukrainian origin.

A Belgian group of researchers has recently found a molecular compound on the Namibian Salsola tubercultiformis shrub, which seems to have an anti-inflammatory effect equivalent to Dexamethasone, without having the same type of side-effects commonly associated with Dexamethasone and Cortisone treatments. This compound, so far only known as compound A, holds some promise as basis for the development of treatments for rheumatoid arthritis and autoimmune conditions

 

Russian Thistle Control. Biocontrol: The Division of Plant Industry’s Biological Pest Control Section has two moth species, Coleophora klimeschiella and C. parthenica, that may be available for redistribution.

Mechanical:  Mowing or pulling young plants can be used to control Russian thistle. However this process may have to be repeated for several years to be successful.

Fire: Prescribed burning is not recommended for control of Russian thistle, since it favors disturbed communities and readily recolonizes burned areas. 

Herbicides:  Dicamba at 0.5 lb., 2,4-D at 1 lb, or glyphosate at 1.5 lb. ai/acre, have been used to successfully control Russian thistle. 

Cultural/Preventive:  Prevent the establishment of new infestations by minimizing disturbance and seed dispersal, eliminating seed production and maintaining healthy native communities.

Integrated Management Summary. For effictive control of Russian thistle, control methods should be accompanied by a program to maintain or enhance the natural plant cover.  As with other annual plants which reproduce by seeds, Russian thistle can eventually be controlled by eliminating seed production