Nature Article
Clematis
11/14/2006
Clematis vitalba
Also known as Old Man’s Beard or Traveler’s Joy
Threat to natural areas: ODA’s Noxious weed list. Clematis competes with English ivy to be the largest invasive species threat to large trees. In areas where this plant has invaded, this species blankets shrubs and trees. Once a tree collapses, the plant continues to grow along the ground in layers that are several feet thick, preventing growth of native vegetation. Old man’s beard spreads quickly along river margins, but will establish in any area not managed.
Description: Deciduous (loses leaves in winter) climbing vine. Each leaf is made up of 5 leaflets (young plants may have only 3 leaflets). Leaves fall off by early January. Bark appears very stringy and easily rubs off on older stems. Clematis is in flower from July to September, and the seeds ripen from September to January. Fluffy grey seed-heads persist over winter.
History: Native of Eurasia. Introduced as an ornamental in Oregon between 1950 and 1970.
Spread: Clematis Can grow five to seven times faster than ivy, with each stem capable of producing 30 feet of growth in one season . Each plant can produce over 100,000 seeds. Seed dispersal is by wind, water, people and other animals. C. vitalba can also spread by fragmentation, when roots are produced from stem fragments and from attached stems. Vegetative spread by fragmentation occurs more often from older plants, since the older stem tissue holds more water and it has higher carbohydrate reserves (Cronk and Fuller, 1995)."
Management: Clematis is best seen from December when most other deciduous plants have lost their leaves and clematis leaves turn pale green. The leaves fall off by early January.
Manual Eradication
Digging out all vines is an effective eradication method. All vines running along the ground and just under the ground must be dug out. Roots broken off or cut off at least 2” under the ground surface do not survive, as the root energy is in the nodes or crown. It can take from one to five or more diggings to eradicate a clematis patch depending on the quality of the digging, the size of the patch, the amount of seed in the ground, the tree canopy density and the other remaining ground cover.
Controlling Reseeding
Planting conifers will help limited new seed germination as clematis needs some sunlight. A good tree canopy will also limit the distance of seed dispersal to 100’ to 200’. A dense ground cover will significantly reduce seed germination. This is not a necessarily a recommended control method, but removing ground cover will decrease competition and will increase the chances of clematis invading an area.
It is important that old man’s beard is not confused with the native species of clematis. The natives usually have only 3 leaflets per leaf and flower in spring, whereas old man’s beard has 5 leaflets and flowers in summer.
For more info:
http://www.nwcb.wa.gov/weed_info/Written_findings/clematis_vitalba.html
This article was written by Kathy Shearin, East Multnomah Soil and Water Conservation District.
