Link to the WSNWCB Home Page link to the About Us page Link to the Weed Laws page Link to the Noxious Weed List Link to the Class A weed list Link to the Class B weed list Link to the Class C weed list Link to the Weed Information page link to the Frequently Asked Questions page Link to the Education page Connect to other Links page Link to Contact Us page

 Click on images to enlarge


Close-up of a Texas blueweed flowerhead


Another view of a Texas blueweed flowerhead


Texas blueweed leaves
Note the glaucous (blue-gray tinge)

One Texas blueweed plant.


Many Texas blueweed plants growing from a rhizome


Note the hairs on the stem and leaves, and how the leaves are clasping the stem


A young plant


Texas blueweed infestation

Texas blueweed
Helianthus ciliaris

Other common names: blueweed, yerba parda

Plant family: Aster (Compositae)
Legal Status: Class A Noxious Weed
Year listed: 1998?
Native to: Grasslands of south-central and southwestern U.S. and northern Mexico.

How would I identify it?
Overall: Member of the aster family with distinctively bluish-green or grayish-green foliage and sunflower-like flowers with yellow outer ray "petals" and dark red or purple-brown centers. Plant can reach height of 1-2 feet tall.

Leaves:

  • alternate or opposite ; lanceolate , or linear
  • attached directly to the stem without leaf stalks (sessile)
  • leaf edges are wavy and have short, stiff hairs

Flowers:

  • composite flowers are 1-1.5 inches wide
  • 10-18 outer ray florets are yellow, less than 0.5 inch long
  • inner disk flowers are reddish to purplish-brown

Line drawings are taken from 1,000 Weeds of North America, copyright of XID Service, Inc and used with permission. Permission granted by the author.

Where does it grow?

Cultivated fields, drainage areas, dry lakes, roadsides

How does it reproduce?

Texas blueweed reproduces primarily by sending out rhizomes, but it also produces numerous seeds. 
  • Rhizome fragments can also sprout new plants, so cultivating the soil can help spread this noxious weed.
  • Although one plant can produce up to 7,500 seeds, only about 1% have been shown to germinate.
  • This small number of viable seeds may help the plant colonize distant areas.

What plants might Texas blueweed be confused with?
The flowers of Texas blueweed could be confused with flowers of the native balsamroots: arrow-leaved (Balsamorhiza sagittata); delta (B. deltoidea) or Carey's (B. careyana). However, the leaf shapes and colors are very different.   A field guide of Pacific Northwest wildflowers can help you identify these, or you can contact the WA Native Plant Society.

Where does it occur in Washington?
Texas blueweed was first detected in a vineyard in Yakima County. This population is very close to eradication. It has also been documented in Twin Falls County, Idaho. If you think you may have seen this weed, please contact your local weed control program or us at noxiousweeds@agr.wa.gov

Why is it listed as a Noxious Weed?
Although native to Texas, it was once considered to be one of the worst weeds of West Texas. It quickly establishes and spreads in disturbed areas and in cultivated fields. It is unpalatable to livestock, so it reduces the grazing quality of fields it invades. It can also significantly reduce crop yields.

How do I control it?
Overall: Depleting the plant's energy reserves by constantly pulling and digging, in combination with the use of herbicides and the planting of native perennial grasses may be the best strategy to control Texas blueweed.

Herbicide: Please refer to the PNW Weed Management Handbook, or contact your county noxious weed coordinator.

Cultural methods: In its native habitat, Texas blueweed grows among other grassland species and does not aggressively outcompete the other plants. The planting of perennial grasses around a Texas blueweed infestation may provide competition for the weed. 

Mechanical methods: Digging up the plant and pulling out rhizomes can be effective; however, rhizome fragments remaining in the soil may grow into new plants. You will want to check area periodically and pull newly emerged plants. You might also try covering small infestations with a tarp to block out sunlight.

Biocontrol: None currently used; Texas blueweed is resistant to the sunflower beetle and the carrot beetle.

For more information

Download our Written Findings

 Last updated March 31, 2007