The Enemy - Common crupina (Crupina vulgaris) is a winter annual that invades range, pastures, and minimal disturbed lands. The plants cotyledons are very fleshy and have a very distinct red mid-vein. Once the rosettes have established they appear like many of the Asteraceae family and have deeply lobed leaves that are pinnately formed. The plant generally sends up one or two vegetative stems that can reach a height of 3 feet. Each stem will have numerous branches off of which will produce up to 5 terminal flowers of purple pedals. The seeds produced by this plant have a formation of stiff bristles around the base of the seed giving the seed the appearance of a dry fly.
The Strategy - As this is fall geminating plant it outcompetes many of the native species. It also grows in the open-ground areas that are normally left for absorption of water and sunlight. As with many asteraceae species this plant is not generally foraged by wildlife or livestock, thus it grows undisturbed. With the amount of bristles along the base of the stem allows the seed to be blown in the wind as well as tied up into fur of animals and spread for long distances.
The Defense - Proper identification is key to controlling this plant. As this is a state and federally listed noxious weed please call your local weed authority to verify its identity and to ensure control methods. Mechanical control is practical but not feasible when more than just few plants are found. There are no biological control insects available for this species which leaves us to the utilization of herbicides. Products of choice would include Milestone and Opensight® (formerly known as Chaparral®). Preferred timing should be in spring or during the budding stage of the plant, which is when most of the plants can be seen.
Dow ™ recommends their herbicides such as Milestone® and Opensight® (formerly known as Chaparral®).
Link to Milestone label. Link to Opensight label.
PLEASE NOTE -The proper use and application of herbicides can be an effective way to control and eradicate noxious and invasive plants. Before using herbicides, always carefully follow the label and safety instructions on the label. While we recommend the use of herbicides as one of the effective tools for integrated pest management, the Idaho Weed Awareness Campaign assumes no liability for herbicide applications.
For more information, click on the link below to download the Idaho's Noxious Weeds Control Guidelines publication produced by the University of Idaho Extension.
U of I Idaho's Noxious Weeds Control Guidelines (183 KB PDF download)