Invasive vines can blanket trees and bushes from sunlight, can spur disease and rot and add considerable weight to trees, eventually weakening and killing them. That's why the conservation district worked with Forest Park Conservancy and Portland Parks & Recreation.
The targeted non-natives: English ivy (Hedera helix), Atlantic/Irish ivy (Hedera hibernica) and Traveler's Joy (Clematis vitalba). On the ground, ivy crowds out native wildflowers, ferns and tree seedlings. Mats of ivy often also can host the Norway rat. Additionally, its shallow roots does little to stop erosion so heavy rain under the plants can dislodge an entire mass of ivy and soil.
The conservation district offers free treatment of canopy weeds on trees on private property in priority areas around park. Landowners must agree to keep the invasives off newly cleared trees and allow checks for five years, according to the conservation district.
– The Oregonian