Participant Info

Species

Rhaponticum repens [Acroptilon repens] [Centaurea repens]

Family

Asteraceae

CommonName

Russian knapweed

Presence

YES

Status

exotic, noxious

EarliestDate

1934

LatestDate

2023

Ecosystem

basin, shrubland, foothill, ruderal, urban

Geobotanical

SSanjuans, UBasin, LBasin

Counties

Alamosa, Conejos, Costilla, Rio Grande, Saguache

Passes

WildlifePreserves

Alamosa, Baca, Blanca Wetlands, Great Sand Dunes

Other Localities

Alamosa (town), Del Norte

PhotoRecords

YES Rich Haswell: Alamosa Co, Alamosa NWR 26 July 2019; Rio Grande Co, South Fork beside Hwy 160 28 July 2013

Comments

Now abundant along the sides of many Basin farm roads, Russian knapweed is clearly a recent arrival. In 1952 Harrington and Matsumura collected a specimen from a road ditch south of Alamosa and could not identify it. Now it is on Colorado's B list of "noxious weeds." Introduced to the southwestern USA in the late 19th century, Rhaponticum repens (widely known as Acropticon repens) has spread through much of the country, with the exception of the deep South. It follows the Rio Grande drainage through New Mexico to the west tip of Texas. Note that R. repens can propagate by root as well as seed, and root buds are viable for up to 75 years. In the San Luis Valley, the species deserves the epithet "invasive."

Annotation