Identification and Reproduction

Identification:

• Russian thistle is an annual shurb that can grow up to 1.5 m tall. 
• In its immature stages it grows erect and branched. Over time it will grow rounded and stems will start to tangle. At maturity shrub can reach over one meter in diameter. 

• Depending on genetics and site conditions stems and leaves may be green, red or even striped. 
• Leaves bear sharp spines. Young leaves are succulent and will mature to become leathery and rigid. 

• Flowers form on the axil of the mature leaf, are pink, white or green and do not have petals.

Reproduction: 

• Russian thistle reproduces by seed. 
• Each plant can produce from 100 to 200,000 seeds in a growing season. 
• As the plant matures it dries out and becomes brittle. Stems break easily in the wind and form tumbleweeds that help disperse seeds. 

Habitat & Ecology

• Prefers sandy textured soils. 
• High tolerance for salinity. 
• Commonly found along beach edges, grasslands and desert communities. 
• But is well adapted to a large variety of habitats. Can also be found on agricultural land, rangeland, abandoned fields, roadsides and coastal areas. 

Impacts

Social: 

• Although grazed when young, this plant becomes too spiny and woody for grazing livestock. 

Ecological: 

• As the seeds begin to mature the plant starts to die off, becoming hard and brittle. This poses as a fire hazard since stems are dry and woody. 
• Outcompetes native species. 
• Obstruct and limits access to stream channels. 

Management

Prevention is a high priority for this species. 

• Plant and maintain healthy ground cover to prevent the establishment of Russian thistle. 

Mechanical/Manual Control: 

• Young plants can be pulled and roots can be dug up. 
• Hoe plants just below the ground level prior to seed set. 
• Stems can be carefully cut prior to flower maturity. 
• Repetitive mowing can help control Russian thistle, but note in some cases this may cause the plant to take low growth patterns. 
• Be sure to wear thick gloves when physically removing the plant.

Chemical Control:

• Glyphosate has the greatest success with Russian thistle. 
• Ensure you are applying before seed set.
• When the plant has become leathery and woody it may be diffucult to control infestations with herbicides. 
• Be sure to read all herbicide labels prior to application. 

Resources

For more details check out the Invasive Species Compendium datasheet on Salsola kali (common saltwort). 

Header photo (Nanosanchez).