Oriental Clematis
Clematis orientalis
Washington State Classification
Class A — Eradication Required Statewide
It forms dense infestations that outcompete native plants and can kill small trees.
Quick Reference
Identification
Growth Habit
It is a moderately vigorous, deciduous climber or a scrambling shrub that typically forms a mass of stems and grows up to around 27 feet long.
Leaves
Leaves are opposite on stems, pinnately compound, with five to seven leaflets. Leaflets have variable size, shape and margins.
Flowers
Flowers are single or in clusters of 3 to many. Flowers are on stems up to around 4 inches long and have 4 yellow to yellowish green sepals (look like petals). Flowers to about 1 inch long. Yellow sepals spread outward and may curve back at maturity.
Fruit & Seeds
Seedheads are a rounded cluster of single seeded achenes. Achenes have hairy styles attached and are around 1 to 2 inches long. Seedheads look like pom-poms.
Impact
It forms dense infestations that outcompete native plants and can kill small trees. It is listed as a noxious weed in Colorado, where it is reportedly difficult to control. It has the potential to establish in a variety of habitats in Washington.
Ecology & Spread
Habitat
Habitats it grows in includes gullies, riverbanks and streambanks, roadsides, open woods, steep hillsides and irrigation canals. Please click here to see a county level distribution map of Oriental clematis in Washington.
Spread Mechanisms
Reproduction
It reproduces by seed and vegetatively by layering and sprouting from root crowns.
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Control Methods
Mechanical
- Colorado recommends hand pulling or digging the plant when the soil is moist, making sure to pull all the roots and carefully bag plant material so as to not scatter seeds.
Biological Control
- There are no known biological controls.