Johnsongrass:
(Sorghum halepense) native of the Mediterranean region

A perennial plant with vigorous rhizomes that can rapidly develop colonies. Johnsongrass is considered one of the 10 most noxious weeds in the world. It is especially troublesome in cotton fields in California and has fast-growing rhizomes that produce new plants.

Weed Wanted Poster and photo courtesy of University of Nevada, Reno Cooperative Extension.

Russian Knapweed:
(Centaurea repens) native of Eurasia

This weed is a member of the sunflower family (Asteraceae), and is an aggressive biennial or short-lived perennial that grows from 1 to 3 feet tall. This species reproduces by seed. Infestations cause soil erosion, decrease biodiversity, and reduce forage for wildlife and livestock on rangelands. It is now widely established in the western U.S. Flowering occurs from June to September.

Weed Wanted Poster and photo courtesy of University of Nevada, Reno Cooperative Extension.

Green Fountain Grass:
(Pennisetum setaceum cupreum) native of Africa

Used primarily for golf courses, fountain grass has been found at the Wash. Fountain grass makes large monocultures (monoculture: a crop or a population of a single kind of organism grown on land), which prevent other plant species from growing within those monocultures. This grass spreads quickly and will carry fire; therefore, it removes native grass/species and then grows rapidly in their place.

Photo courtesy of National Park Service.

Five Hook Bassia (aka smother weed):
(Bassia hyssopifolia)

This weed is easily transported by using its hooks to grab on to things. It also creates monocultures (similar to those of the fountain grass). It sticks predominantly to road margins and disturbed areas.

Photo courtesy of USGS Northern Prairie Wildlife Research Center.