ENVS 605

What is it?

Absinth wormwood is native to Eurasia, the Middle East and North Africa and was introduced to North America in the early 19th Century to be cultivated for medicinal use. Absinth wormwood is a long-lived perennial that possesses a strong sage odor and bitter taste. Plants grow 2 to 4 feet in height and are prolific seed producers. It has a taproot that can reach 2 inches in diameter and shallow lateral fibrous root branches that can extend up to 6 feet long in all given directions. Plants are woody at the base and regrow from the soil level each spring. The stems are numerous and are covered with fine, gray hairs while the leaves are blue-olive green, alternate and highly divided. Flowers are small, yellowish and arranged in large, spike-like panicles.

 

 

Why is it a problem?

Absinth wormwood is problematic because of its tendency to exploit disturbed sites as well as moist and shady soils. It occurs in 5,000 to 7,000 feet elevation and is considered a weed in pastureland, cropland, and rangeland. Absinth wormwood is listed as having poor palatability by horses. The seed viability is estimated to be 3 to 4 years and are easily scattered by wind, water, animals, and in hay.

 

 

Management techniques:

The key to effective control of Absinth wormwood is a combination of control methods.

 

• Compared to most perennials, it is fairly easy to control with chemicals in combination with mechanical control such as hand pulling.

• Make sure to pull all of the roots including the horizontal roots. Bag the plants carefully so as to not scatter seeds if removed after flowering.

• Mowing may be an option if done before the plants go to seed resulting in a stressed plant.

• Herbicides can also control absinth wormwood but special care must be taken when using them. For more information visit www.colorado.gov/cs/Satellite/ag_Conservation/CBON/1251618780047  Or call the State Weed Coordinator at the Colorado Department of Agriculture,Conservation Services Division, 303-239-4100.

 

 

What can we do?

It is important to continue working to eradicate Absinth Wormwood in this area by following the above management techniques. Absinth wormwood is designated as a “List B” species in the Colorado Noxious Weed Act. It is required to be either eradicated, contained, or suppressed depending on the local infestations.

 

 

General Information on Absinth Wormwood

 

Colorado State University Extension:

• PDF, identification and impacts of Absinth Wormwood

Colorado Weed Management Association:

• Website that provides information about Absinth Wormwood