English Ivy
Hedera helix 'Baltica', 'Pittsburgh', and 'Star'; Hedera hibernica 'Hibernica
Washington State Classification
Class C — Widespread, County-Selected Control
Ivy can outcompete native plants, reducing animal foraging habitat.
Quick Reference
Identification
Growth Habit
English ivy is an evergreen, perennial vine. It can grow as a vine (juvenile form) or a more erect, shrubby stemmed form (adult form). Vines can grow up to 99 feet. In its juvenile form, the plant produces adventitious roots that allow vines to anchor to vertical surfaces.
Leaves
Leaves are alternate each other on the stems and leathery, with long petioles and have two forms: adult and juvenile leaves. Juvenile leaves are deeply 3 to 5 lobed and 1.6 to 4 inches long and wide. Adult leaves occur on flowering stems and are primarily un-lobed leaves and egg-shaped to diamond shaped. Only young leaves are hairy.
Flowers
English ivy matures to produce adult stems and flowers when it begins to grow vertically. The small (0.2 to 0.3 inch), bisexual, greenish-white flowers occur in umbrella-like clusters in the fall. The juvenile stage, time before it flowers, may be for 10 years or longer.
Fruit & Seeds
The dark colored fruits (dark blue to black, berry-like drupes) mature in the spring. Each fruit is around 0.16 to 0.31 inch (4 to 8 mm) wide and contains 4 to 5 seeds.
Impact
Ivy can outcompete native plants, reducing animal foraging habitat. It inhibits regeneration of understory plants and kills understory and overstory trees by shading them out. Ivy may cause storm damage trees by the added weight in the canopy that also may act as a sail. The sap of the stems can cause skin irritations and rashes to sensitive individuals. Consuming large amounts of leaves and fruits can be toxic to people and cattle.
Ecology & Spread
Habitat
Ivy grows in a variety of landscaped areas, escaping to disturbed forests at a range of elevations. It can grow in a variety of soil types and light conditions. Habitats include woodlands, forest edges, riparian areas, fields, hedgerows, coastal areas, and disturbed habitats. Please click here to see a county level distribution map of the four listed cultivars of English ivy in Washington.
Spread Mechanisms
Reproduction
During its juvenile stage, ivy spreads rapidly by vegetative stem growth while mature plants can also spread by seed. Stem and root fragments can resprout. On average, 70% of ivy seeds are viable and plants can produce thousands of fruits per year.
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Control Methods
Mechanical
- Plants can successfully be pulled by hand or dug out. Plants are easier to pull out of the ground when the soil is moist from rain. In western Washington, fall through the spring, before dormant plants begin to grow, is a great time to pull ivy. Be careful when pulling ivy in the spring and summer to not damage native and other desirable plants in the area. In the case of plants climbing on trees, vines can be cut at around waist to chest height, pulling away the lower part of the stems away from the base of the tree, to kill the upper portions of the vine. It will take some time but the leaves on the cut stems still in the trees will slowly die and fall off.
Cultural / Prevention
- Mow it close to the ground, then dig up the roots, removing as many as possible. After top growth is cleared as much as possible, cover with a double layer of landscape fabric, black plastic, or cardboard, covered with bark or mulch. To control ivy growing vertically, cut and pull it down in sections, and dig out the roots.