Identification and Reproduction

Identification: 

• Texas blueweed is a species of sunflower that grows from creeping rhizomes. 
• Stems extend upright and range between 40 to 70 cm tall. 

• Can appear clumpy, as numerous shoots will arise from the underground rhizomes. 
• Leaves and stems are blue-green to grey-green in colour and narrowly lance-shaped.
• Leaves attach directly to the stem, have wavy margins and stiff hairs. 
• Blooms occur from June through October. Flowers are 2-4 cm wide, have yellow ray florets and reddish disk florets. 

Reproduction: 

• Texas blueweed can spread through rhizome fragments and seed production. 
• Often rhizomes are fragmented and transported by agricultural machinery.
• Seed germination is slow and regarded as insignificant in local spread.  

Habitat & Ecology

• It grows rapidly on recently disturbed sites, cultivated lands, ditches and roadsides. 
• It has the most invasive characteristics on cultivated lands and does not appear to invade natural environments. 
• Currently absent from Canada but distributed throughout the the southwest of US as it is native to Texas and Mexico. 

Impacts

Social: 

• It is aggressive, forming extensive colonies where possible. 
• Crop yields and qualities are reduced. 
• Contaminates seed crops. 

Management

Prevention is a high priority for this plant. 

• Use clean, high-quality seed mixtures that are certified. 
• Ensure that equipment, vehicles and tools are clean and free of debris. 
• Continously monitor cultivated sites for new infestations.
• Planting of perennial grasses can prevent Texas blueweed establishment.   
• Report this plant if you think you have seen it. 

Resources

For more for details check out the Invasive Species Compendium datasheet on Helianthus ciliaris (Texas blueweed). 

Header photo (J L Johnson).