Russian-thistle

Images above: Left: Russian-thistle seedling (Joseph DiTomaso, University of California, Davis). Right: Russian-thistle inflorescence (Joseph DiTomaso, University of California, Davis).

Identification

Other common names:  Russian tumbleweed, Russian cactus, tumbling Russian-thistle, glasswort, burning bush, saltwort, prickly glasswort, wind witch, tumbleweed

Family:  goosefoot family, Chenopodiaceae

Habit:  Erect, branched summer annual herb.

Description:  The seedling stem is striped with reddish-purple streaks.  Cotyledons are fleshy, needle-like, and 0.8-2” (2-5 cm) long by less than 0.1” (0.25 cm) wide.  The first true leaves of the seedling appear opposite and are fleshy, similar in size and shape to the cotyledons, and tipped with spines.  The leaves become smaller, flattened, and less fleshy as the plant grows.  Mature plants are 0.5-4 ft (15-120 cm) tall, often as wide as tall, profusely branched, and bush-like in appearance.  Stems have short, stiff hairs (or are occasionally smooth) and have reddish purple streaks.  The stems become stiff and dry as the season progresses.  Leaves are alternate, hairless or with short hairs, thin and linear or needle-shaped, 0.25-2.5” (0.6-6 cm) long by 0.04-0.25” (0.1-0.6 cm) wide, and have a stiff, prickly spine at the tip.  Mature plants may break at the base and become a tumbleweed.  The root system is a long taproot.  Small, petal-less flowers develop in the leaf axils on the upper portions of the stem between a pair of 0.02” (0.05 cm) long, spine-tipped bracts.  As the flower matures, five pale green to red, petal-like, membranous sepals enlarge to 0.15-0.3” (0.4-0.8 cm) wide and surround the single developing seed.  The seed is conical, gray-brown, and 0.2-0.3” (0.5-0.8 cm) in diameter. 

Similar species: Kochia [Bassia scoparia (L.) A.J. Scott] has similarly striped stems and a similar growth habit to Russian-thistle.  Kochia leaves, however, are broader, lack spines, and have dense, greyish hair on all surfaces, while the leaves of Russian-thistle are hairless or have only short hairs and are spine-tipped. 

Management 

This is the dominant broadleaf weed in dry land grain production areas and heavy infestations can prevent adoption of less competitive rotational crops such as spring peas or canola (Young 2006).  Because Russian-thistle primarily emerges in early spring, rotation with late spring and summer crops allows most of the previous year’s seeds to emerge and be killed by tillage before planting.  Similarly, due to the very early season emergence of Russian-thistle, a brief fallow (1-2 weeks) before planting an early season crop can help control the weed (Chepil 1946).  Because Russian-thistle is intolerant of shade and relatively slow growing, crop competition is an important control mechanism (Halvorson and Guertin 2003).  Thus, choosing sowing time to maximize early crop growth rate, choosing competitive cultivars, increasing crop density, and decreasing distance between grain rows all help reduce the competitiveness of the weed.  Accordingly, Russian-thistle emergence and growth is suppressed more by a crop of established winter wheat than by spring wheat (Young 1986).  Also, inclusion of green manure crops such as yellow sweetclover into the rotation can suppress this weed (Blackshaw et al. 2001).

Conventional tillage reduces abundance of this species, whereas it thrives in no-till or reduced tillage fields with surface residue cover (Beckie and Francis 2009).

Russian-thistle can accumulate over 93% of its total dry matter production after grain harvest, so control of this weed after harvest is essential (Young 1986).  Shallow undercutting with wide, low-pitch V-blades after grain harvest can completely prevent seed production while retaining 90% of the stubble for prevention of erosion (Schillinger 2007).

Close mowing of newly emerged seedlings will kill most of them.  Mowed or rotationally grazed forages compete with the weed, and mowing and treading kills plants and helps prevent seed production by those that remain (Halvorson and Guertin 2003).

Ecology

Origin and distribution:  Russian-thistle is a native of Russia that was introduced into South Dakota in flax seed in the mid 1870’s.  It presently occurs throughout the U.S.A. and southern Canada, except in the deep south.  In Eurasia its range extends from China through most of Europe and into North Africa.  It has been introduced into southern Africa, Australia and parts of Central and South America (Beckie and Francis 2009).

Seed weight:  1.1-1.6 mg (Young and Whitesides 1987), 1.7 mg (Stevens 1932).

Dormancy and germination:  Most seeds are dormant when dispersed from the mother plant and several months are required before they will germinate (Crompton and Bassett 1985, Halvorson and Guertin 2003).  Germination of mature seeds collected in fall will only occur under a restricted range of temperatures (68/41 °F = 20/5 °C day/night alteration is optimal), whereas in April, seeds will germinate well under a wide range of fluctuating temperature combinations ranging from 28 to 86 °F (-2 to 30 °C) (Young and Evans 1972).  Seeds can germinate, however, at daytime temperatures as low as 36 °F (2 °C) with night temperatures below freezing (Halvorson and Guertin 2003).  Winter chilling is not required for after-ripening (Young and Evans 1972).  In a field study, germination peaked when soil temperatures were 59-77 °F (15-25 °C) during the day and 32-41 °F (0-5 °C) at night.  In a lab study, germination was best at 86/68 to 95/77 °F (30/20 to 35/25 °C) day/night temperatures (Khan et al. 2002).   Fluctuating temperatures appear to promote germination, but the species is relatively unaffected by light (Crompton and Bassett 1985).  Germination of Russian-thistle is not limited by dry soil conditions that would inhibit germination of other species (Young and Evans 1972).  Germination can occur at high salt concentrations only at temperatures greater than 68 °F (20 °C), but germination of seeds removed from salt conditions is best at lower temperatures (e.g. 59/41 °F = 15°/5 °C) (Khan et al. 2002).  This germination response is adapted to western desert conditions whereby evaporation and saline conditions increase as seasonal temperatures increase, but intermittent dilution of salt concentrations and cooler temperatures are associated with rainfall.  These traits coupled with a capacity to germinate very rapidly (in minutes to hours) allow Russian-thistle to establish in environments where favorable conditions are highly transitory (Halvorson and Guertin 2003).

Seed longevity:  Although a few seeds may remain viable deep in the soil for many years, most seeds remain viable for no more than one to two years (Halvorson and Guertin 2003).  In a Nebraska experiment, seed did not survive for one year (Burnside et al. 1996).  In a Saskatchewan experiment in which seeds were sown on cultivated soil in the fall, 31% emerged in the next spring, less than 0.5% the second year, and only 2 individuals (0.04%) the third year (Chepil 1946).

Season of emergence:  Seedlings mostly emerge in early spring, with emergence continuing through late spring (Beckie and Francis 2009, Chepil 1946, Crompton and Bassett 1985, Evans and Young 1972, Halvorson and Guertin 2003, Young 1986).  Russian-thistle also can emerge intermittently following light rainfall (Halvorson and Guertin 2003, Young 2006).

Emergence depth:  Seedlings emerge best from seeds located within the surface 0.4” (1 cm) to 1.0” (2.5 cm) of soil (Halvorson and Guertin 2003).  A few seedlings can emerge from 2.4” (6 cm), but none from 3.2” (8 cm) (Evans & Young 1972).  Emergence from seeds on the soil surface is low unless crop residue is present (Halvorson and Guertin 2003) and/or the relative humidity of the atmosphere is very high (Young and Evans 1972).

Photosynthetic pathway:  C4 (Beckie and Francis 2009, Crompton and Bassett 1985, Elmore and Paul 1983, Halvorson and Guertin 2003, Nord et al. 1999)

Sensitivity to frost:  Russian-thistle, both as seedlings and as mature plants, is killed by hard frost (Crompton and Bassett 1985, Halvorson and Guertin 2003).

Drought tolerance:  Established Russian-thistle plants are extremely drought tolerant and highly water efficient (Crompton and Bassett 1985, Halvorson and Guertin 2003).  The root system is at least five times as long as shoots and can extend 5 ft (1.5 m) laterally and 6 ft (1.8 m) vertically (Pan et al. 2001), which partially explains the rapid access to and depletion of soil water by this species (Schillinger and Young 2000).  However, seedlings are relatively sensitive to drought during the establishment period (Thomas and Redsteer 2019).

Mycorrhiza:  Russian-thistle does not form mycorrhizal associations (Halvorson and Guertin 2003, Harley and Harley 1987, Pendleton and Smith 1983).  Some evidence indicates that growth can be inhibited by mycorrhizal fungi (Beckie and Francis 2009).

Response to fertility:  Compared with most crops and other weed species, Russian-thistle growth is not responsive to nitrogen (Blackshaw et al. 2003).  The species is very good at taking up N when it is in short supply, however, and it concentrates high levels of nitrates (> 5% N) in shoots under high fertility conditions (Blackshaw et al. 2003), a capacity that can enhance its competitiveness with other N-requiring plants (McLendon and Redente 1992).  Russian-thistle is also remarkably unresponsive to P (Blackshaw et al. 2004).

Soil physical requirements:  Russian-thistle occurs primarily on dry, sandy soils.  It is also common on loam and silty alkaline soils in prairie regions but it is uncommon on clay soils.  It tolerates and thrives on saline soils that inhibit most plant species (Banerjee et al. 2006).  It rarely occurs in wet areas.  Seedling emergence is poor on compacted soil (Beckie and Francis 2009, Crompton and Bassett 1985, Evans and Young 1972, Halvorson and Guertin 2003).

Response to shade:  The species does not tolerate shade (Halvorson and Guertin 2003).

Sensitivity to disturbance:  Small plants cut just above the seed leaves do not survive (Crompton and Bassett 1985), which indicates that early season mowing may control the species.  Older plants recover from mowing by developing prostrate stems below the cutting level, requiring additional mowing or other control practices for control (Halvorson and Guertin 2003).  After stems are cut during small grain harvest, the root system rapidly regrows at a rate faster than shoot regrowth (Pan et al. 2001).  Overall regrowth, if left unchecked after harvest, can lead to substantial seed production by fall (Young 1986).

Time from emergence to reproduction:  Flowering begins in mid-June and can continue until frost (Beckie and Francis 2009, Young 2006).  Seed production occurs from August thru fall (Beckie and Francis 2009, Halvorson and Guertin 2003).

Pollination:  Russian-thistle is wind pollinated and self-compatible (Beckie and Francis 2009, Crompton and Bassett 1985, Halvorson and Guertin 2003).

Reproduction: Estimates of seed production vary greatly from 2,000 to over 100,000 seeds per plant (Halvorson and Guertin 2003).  Very large plants have been reported to produce up to 150,000 seeds (Stallings et al. 1995, Young 1986), but plants growing in competition with crops typically produce 5,000 to 17,000 seeds (Young 1986). 

Dispersal:  Russian-thistle grows in a ball-like shoot structure that frequently breaks off at the base after senescence and rolls in the wind, dropping seeds as it bounces along (Beckie and Francis 2009, Crompton and Bassett 1985, Halvorson and Guertin 2003).  Winds with gusts up to 61 mph are required to break off stems of recently senesced plants (Baker et al. 2008).  Plants tumble an average distance of 2078 yards (1900 m) and a maximum distance of 2.5 miles (4.1 km) until stopped by fence-lines, roadways or other obstacles (Stallings et al. 1995).  Tumbleweeds caught on railroad cars can spread seeds across the landscape for long distances (Halvorson and Guertin 2003).  Plants retain 26-51% of seeds after tumbling approximately 1 mile, ensuring seed dispersal over large distances (Stallings et al. 1995).  Seeds also can be spread in waterways and contaminated crop seeds or straw (Halvorson and Guertin 2003).  Seeds present in the Columbia River and irrigation water laterals had a 56% germination potential (Kelley and Bruns 1975).

Common natural enemies:  The native caterpillars Coleophora parthenica and C. klimeschiella are sufficiently destructive to Russian-thistle that they have been released in Canada as biological control agents (Crompton and Bassett 1985).  Coleophora parthenica also was introduced into the Coachella Valley of southern California, but, although larvae infested most Russian-thistle plants, it had little effect on growth or population levels of this species (Goeden and Ricker 1979).  The rust fungus Uromyces salsolae, the anthracnose fungus Colletotrichum gloeosporioides, and the bare spot fungus Rhizoctonia solani have shown potential to suppress growth under controlled conditions (Beckie and Francis 2009).

Palatability:  While young and before spines form, Russian-thistle can provide a good source of forage for livestock and native animals (Beckie and Francis 2009, Halvorson and Guertin 2003).  Oxalates and nitrates in the tissue of Russian-thistle can poison sheep (Crompton and Bassett 1985).  Nitrates become a problem when the plant is growing on well fertilized soils (Crompton and Bassett 1985).  Salinity enhances forage quality of Russian-thistle, reduces nitrate and oxalate concentrations at full flower, and creates good forage potential on arid lands (Fowler et al. 1992).

Note:  Russian-thistle pollen is an important contributor to summer hay fever in regions where it is common (Beckie and Francis 2009, Crompton and Bassett 1985).

References:

• Baker, D. V., K. G. Beck, B. J. Bienkiewicz, and L. B. Bjostad.  2008.  Forces necessary to initiate dispersal for three tumbleweeds.  Invasive Plant Science and Management 1:59-65.
• Banerjee, M. J., V. J. Gerhart, and E. P. Glenn.  2006.  Native plant regeneration on abandoned desert farmland: Effects of irrigation, soil preparation, and amendments on seedling establishment.  Restoration Ecology 14:339-348.
• Beckie, H. J. and A. Francis.  2009.  The biology of Canadian weeds. 65. Salsola tragus L. (updated).  Canadian Journal of Plant Science 89:775-789.
• Blackshaw, R. E., R. N. Brandt, H. H. Janzen, T. Entz, C. A. Grant and D. A. Derksen.  2003.  Differential response of weed species to added nitrogen.  Weed Science 51:532-539.
• Blackshaw, R. E., R. N. Brandt, H. H. Janzen, T. Entz.  2004.  Weed species response to phosphorus fertilization.  Weed Science 52:406-412.
• Blackshaw, R. E., J. R. Moyer, R. C. Doram, and A. L. Boswell.  2001.  Yellow sweetclover, green manure, and its residues effectively suppress weeds during fallow.  Weed Science 49:406-413.
• Burnside, O. C., R. G. Wilson, S. Weisberg, and K. G. Hubbard.  1996.  Seed longevity of 41 weed species buried 17 years in eastern and western Nebraska.  Weed Science 44:74-86.
• Chepil, W. S.  1946.  Germination of weed seeds I. Longevity, periodicity of germination, and vitality of seeds in cultivated soil.  Scientific Agriculture 26:307-346.
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• Fowler, J. L., J. H. Hageman, K. J. Moore, M. Suzukida, H. Assadian, and M. Valenzuela.  1992.  Salinity effects on forage quality of Russian thistle.  Journal of Range Management 45:559-563.
• Goeden, R. D., and D. W. Ricker.  1979.  Field analyses of Coleophora parthenica (Lep.: Coleophoridae) as an imported natural enemy of Russian thistle, Salsola iberica, in the Coachella Valley of southern California.  Environmental Entomology 8:1099-1101.
• Halvorson, W. L., and P. Guertin.  2003.  Salsola L. spp.  USGS Weeds in the West Project:  Status of Introduced Plants in Southern Arizona Parks Factsheet.  38 pp.
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• McLendon, T., and E. F. Redente.  1992.  Effects of nitrogen limitation on species replacement dynamics during early secondary succession on a semiarid sagebrush site.  Oecologia 91:312-317.
• Nord, C. A., C. G. Messersmith, and J. D. Nalewaja.  1999.  Growth of Kochia scoparia, Salsola iberica, and Triticum aestivum varies with temperature.  Weed Science 47:435-439.
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