By Dider Gincig

Special to the Journal

Invasive Clematis vitalba (Old Man’s Beard, or also called Traveler’s Joy) is one of the largest invasive species and a threat to trees, eventually causing them to collapse.

Once the tree collapses, C. vitalba continues to grow along the ground in layers that are several meters thick, preventing the regeneration of anything below it.

Any light necessary for plant growth is blocked out. It prevents growth of native vegetation, and each stem can produce 30 feet of growth in one season.

Homeowners can do their share by cutting vines and removing roots, and by organizing neighborhood work parties. You can call Judy Jackson and Jason Ontjes, field assistant at the San Juan County Noxious Weed Control Program, as they will respond to homeowners’ willingness to help with this invasive species, and will be purchasing a pair of loppers to loan to the public (376-3499 or email at judy@sanjuanweeds.org, jason@sanjuanweeds.org).

It is in bloom now, thus easier to see, but also in seed (each plant can produce over 100,000 seeds).

Seedlings can be hand pulled. Larger stems need to be cut. It is okay to cut them low to the ground and as high as you can reach, but the material should not be moved due to the likelihood of dispersing seeds.

They have prolific seed production with wind dispersal and a vine quickly recovers from physical damage, with the ability to re-sprout when roots are produced from stem fragments and from attached stems.

All vines running along the ground and just under the surface must be dug out. Roots broken off or cut off at least two inches below the surface usually do not survive.

Eradication requires multiple treatments. Planting conifers will help limit germination by reducing available sunlight. Dense native ground cover may also significantly reduce seed germination.

The impacts are visible and spreading as this species climbs over the forested areas with a rapid growth rate. Growing in abundance on Orcas and San Juan islands, invasive Clematis vitalba is listed as Class C in Washington but is not required for control in San Juan County at this time, though controlling it is recommended.

The approach the county is taking is education, providing management strategies, and resource assistance. The county has the ability to control and prevent this plant from spreading. To designate it for control in this county, it would have to be approved by the county’s noxious weed control board. Board representatives are open to public input at http://sanjuan.wsu.edu/noxious/.

The county Public Works Department does not consider it a priority to remove noxious weeds along county roads. Public input to county commissioners and other officials might be helpful with that policy.

There are various financial issues with the disposal of noxious weeds. The Noxious Board will be working with transfer stations to establish the most sensible and economic way without necessarily having to ship noxious weeds off island.

If you have Clematis vitalba on your land or would like to be involved in reducing its effects, get out there and make a difference!

Meanwhile, I’ll be out there doing what I can to help educate the public and motivate a call for action.

— Editor’s note: Dider Gincig provides public outreach materials and information for San Juan County Noxious Weed Board.