Western clematis is a flowering woody perennial commonly grown in USDA cold-hardiness zones 5a to 7a. It tolerates altitudes to 4,000 feet, arid to coastal climates with annual rainfall of 9 to 21 inches and winter temperatures to 0 degrees Fahrenheit. Western clematis is controlled through pruning or removal.
Western clematis grows by twining vines that may reach 60 feet long. This twining plant, native to the western United States, is not invasive but may spread into gardens or shrubs. The plant lives up to 25 years and needs control when it grows too close to buildings or desirable landscaping.
Western clematis directional growth is controlled by guiding it along fences, trellises or other supports. When main vines are guided over irregular or open ground, it spreads into dense mats that reduce soil erosion and runoff. Prune the plant after flowering to control its desired shape and size.
Control the spread of western clematis by removing unwanted plants. Dig out small clematis as seedlings. Remove larger western clematis by digging or applying herbicide. Use herbicides specifically for controlling woody plants and vines. Reapply as needed if the plant shows new growth.