I would like to know about controlling Clematis vitalba which is invading my garden from next door.
Clematis vitalba, also known as Traveler’s Joy or Old Man’s Beard, may be a challenge to control without some cooperation from your neighbor. If your neighbor will agree to keep it from going to seed, that will help a little. You might also persuade the neighbor to eradicate the plant, which is a Class C Noxious Weed in Washington State (and in King County), meaning that it is widespread, and enforcement of control is optional but recommended. It is listed in the GardenWise booklet (copies available in the Miller Library and in some local nurseries) which describes noxious weeds and alternative plantings.
The Northwest-based website of Rainyside Gardeners has useful directions on getting rid of this vine. Here is an excerpt:
“The first step in the removal of traveler’s joy requires cutting the plant’s stems above the ground. It is important to make sure the space between the two pieces is large enough to prevent the stem from reattaching itself to the root. Stems can reroot if left in contact with the ground for a long period of time, so periodically move any portions of the plant left in situ. Do not tug on the stems still in the trees. Gravity never sleeps! Pulling on the stem might bring down more than you can handle (all the stem, host branches, or possibly the entire tree).
Digging out the roots of the traveler’s joy is surprisingly easy, but these roots may extend for a long way. Often the roots will be a tangle of overlapping coils and may even come from a distant plant. After that task has been accomplished, a gardener will need to be on the look out for the seedlings that may pop up.
Traveler’s joy is an insidious pest because it readily reproduces vegetatively and by wind cast seeds. The vine-like growth habit spreads myriad possibilities of reproduction over a large area. If a neighbor has an untended C. vitalba, a gardener may find themselves cleaning up their neighbor’s mess.
Because the roots run shallow, simple ‘pull and pile’ is the best method to kill C. vitalba. Some sources suggest bagging all removed sections of the plant, for an off-site disposal, or burning on-site. Burning adds to the air pollution and may attract unwanted attention from authorities who carry weapons. Therefore, burning should be avoided. Simply moving the pile periodically, or placing the debris on an impervious surface until it has died and begins to decompose, may be all that is needed.”