Weed of the Month: Western Clematis
 | Author:
Allison Kosto, MSU Broadwater County Extension Agent
MSU Broadwater County Extension Agent |
Weed of the Month: Western Clematis
Allison Kosto
MSU Broadwater County Extension Agent
This plant is often inconspicuous until it becomes obnoxious. It is a native plant by many names including western clematis, white clematis, virgin’s-bower or a combination of any of these names. It has an interesting history with the Native Americans. It was used as a horse stimulant. The root was said to be scraped and placed in front of the nose of fallen or exhausted horses to wake them. It was also used by the Native Americans as a remedy for colds and sore throats.
Description & Habitat
Western clematis is native to the western half of the United States and Canada. It is one of the few native vines found in Montana. It tends to prefer riparian areas and riverine that are mostly shaded. It is often associated with deciduous trees and shrubs and is less common among evergreen trees.
A member of the buttercup family, western clematis is a perennial (life cycle of more than two years) semi-woody vine. Older veins are woody with shredded bark. It is capable of growing more than 30 feet long by climbing into the canopy of trees and shrubs. Western clematis has clusters of white flowers that grow from the leaf axils. The fruit develops into fluffy bundles of seeds that look like cotton balls. The vines and the fruits remain visible throughout the winter. It has a taproot.
Under the right conditions, western clematis can choke out desirable plants and cover shrubby vegetation. The woody vines can become heavy weighing down branches, leading to their collapse. It can become a nuisance when it climbs structures, fences and ornamental plants. Some sources also indicate the plant is poisonous. Members of this plant family contain alkaloids that cause gastrointestinal distress, depression, nervous system paralysis and even death in extreme cases.
Management
Very little research has been done on the control and management of western clematis. Typically, full control is not necessary. Reducing the population in high-density sites or removing it from areas where it is not wanted is typically enough.
The most effective management strategy is to prevent it from going to seed. Small infestations can be hand-pulled, hoed or dug. Mowing consistently can be effective where practical. Tilling may be effective if followed by reseeding. The plant can regrow from the root, so persistence is key.
Herbicide options are limited due to its growing pattern. It’s difficult to use herbicides without harming the desirable plants. One technique is to use a paintbrush by dipping or spraying it with an herbicide and “painting” the vines and leaves of the plant. Herbicide options include Change Up, E-2, Escalade 2, Quincept, Roundup, Sure Power and Vengeance. Even after the plant has been killed, the woody vines will persist for many years and may need to be removed. Always read and follow the entire label when applying herbicide. Common chemical names are used for clarity but does not imply endorsement of a product or brand.
For assistance on weed identification and management, contact the MSU Extension Office in Broadwater County at 406-266-9242.
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PhotoCredit: Photo Credits: Allison Kosto
Image 1 Caption: Western Clematis
Photo Credits: Allison Kosto
