Annual weed out competing Cheatgrass was recently found in Lewis and Clark County

Ventenata (Ventenata dubia (Leers) Coss. Family: Poaceae) is commonly known as wiregrass or North African grass. Ventenata is a non-native winter annual grass that has recently spread from Western Montana into nearby Lewis and Clark County. Ventenata is relatively new to Montana and has the potential to impact range, pasture, wild lands, and annual crops. Its low forage value and shallow root structure can lead to decreased agricultural production and increased risk of soil erosion. Some canyon grasslands in Idaho were once dominated by cheatgrass, and are now infested by ventenata.

Ventenata originates from Eastern Europe and was first found in North America in the early 1950s in Washington and Idaho. It was first documented in Montana in the mid-1990s. Though ventenata is not listed on Montana’s noxious weed list, recent infestations are of growing concern for land managers due to its continual spread and economic, as well as ecological, impacts in other areas.

Ventenata is a winter annual grass that typically grows 6-18 inches tall. It has a distinguishing long, membranous ligule (up to 0.3 inches in length) with reddish-black nodes. Seedlings and mature leaves are narrow and folded lengthwise. Ventenata seeds have bent

and twisted awns like wild oat (Avena fatua). The awns are developed, bent and twisted by June and July, reaching about 0.1 inch in length. At maturity, ventenata has awns like cheatgrass and Japanese brome but awns of ventenata are bent and twisted. In addition, cheatgrass turns reddish-purple upon maturity while ventenata remains green to tawny brown.

Ventenata mostly germinates in fall, but some germination can take place in spring. It is adapted to characteristic Mediterranean climates with cool, wet winters and hot, dry summers. Ventenata mostly germinates in fall, but some germination can take place in spring. Field observations suggest it can grow in areas with moderate annual precipitation ranging from 14 to 44 inches and elevations ranging from 33 to 5,900 feet.

Ventenata reproduces by seeds. Each plant produces about 15-35 seeds. It is known to spread through roadways and contaminated forage. Contaminated seeds from Idaho and Washington are suspected as a major source for infestations in Montana. Awns can easily attach to fur, clothing, and machinery.

Ventenata is generally unpalatable for livestock and wildlife as it matures and can decrease forage value. Additionally, the shallow root system creates conditions conducive to soil erosion. In Idaho an estimated reduction of 50% forage yield and crop quality occurred a few years after initial infestations.

Information for this article was taken from the Montana State University Montguide MT 201810AG. The Montguide was written by Audrey Harvey and Jane Mangold from the MSU Department of Land Resources and Environmental Sciences. The document is available online. Hard copies are available at the Chouteau County Extension office. The office is located in the green building next to the Chouteau County courthouse.

Montana State University, U.S. Department of Agriculture and Montana Counties Cooperating. MSU Extension is an equal opportunity/affirmative action provider of educational outreach.