Hedera helix L.
- There are 3 types of ivy in our area that are nearly indistinguishable in the field. All 3 are considered invasive and the identification and treatment for each is the same.
- Ivy is an evergreen climbing vine that attaches to the bark of trees, brickwork, and other surfaces by way of small root-like structures.
- Leaves may be either angular with 3-7 points, or rounded with a single terminal point. Both leaf types may be found on the same plant.
- Stems can be several inches across in good growing conditions. Leaves are dark green with pale veins, waxy to somewhat leathery, and arranged alternately along the stem.
- Aggressive in its spread, ivy displaces native plants, dominating beneficial habitat while harboring unwanted rodents.
Habitat & Distribution
- Ivy infests woodlands, forest edges, fields, hedgerows, coastal areas, salt marsh edges, and other upland areas, especially where some moisture is present.
- It thrives in a wide range of soil pH but prefers slightly acidic soils.
- It is often associated with land disturbance, either human-caused or natural, but can also invade otherwise intact, healthy woodlands.
Reproduction & Spread
- Ivy spreads through vegetative regrowth. New plants can grow from cut or broken pieces of stem.
- Ivy is also spread by seeds, which are often dispersed by birds. Ivy’s dark-purple berries are produced wherever plants receive sufficient sunlight. Typically, these conditions occur on vines climbing tree trunks, but mature, fruiting plants can be found at ground level, as well.
Integrated Pest Management
- Integrated Pest Management (IPM) involves selecting from a range of possible control methods to match the management requirements of each specific site. The goal is to maximize effective control and to minimize negative environmental, economic, and recreational impacts.
- Use a multifaceted and adaptive approach. Select control methods reflecting the available time, funding, and labor of the participants, the land use goals, and the values of the community and landowners. Management will require dedication for a number of years and should allow flexibility in methods.
- Survey the area for weeds, set priorities, and select the best control method(s) for the site.
- Control practices should be selected to minimize soil disturbance. Minimizing disturbance prevents further infestations of weeds.
- Begin work on the perimeter of the infested areas first and move inward toward the core of the infestation.
- Monitor the site and continue to treat plants that germinate from the seed bank.
- Re-vegetate treatment areas with site-suitable native plants to improve ecosystem function and prevent new infestations.
Early Detection and Prevention
- All trees are susceptible to ivy infestation. Uninfested areas should be surveyed yearly to locate and pull seedlings before they spread. Winter surveys are most effective for this evergreen plant.
- Monitor for new plants and re-treat as necessary. Ensure any existing plants do not produce and release seed. Remove, bag, and dispose of plants and seeds as trash, or burn pulled material (when fire regulations allow). Ivy fragments left on the ground may re-root and continue growing.
- Prevent the additional spread of ivy by thoroughly cleaning tools, boots, and vehicles after working in or traveling through an infested area.
- Do not buy ivy at nurseries or garden centers; consider planting comparable non-invasive plants. It is not legal to sell ivy in Oregon.
Manual, Mechanical, & Cultural Control
- Birds may nest in ivy growing on trees or on the ground. Before you start any control method, be sure to survey for nesting birds.
- Established infestations will require control of both tree ivy (growing up established trees) and ground ivy (growing along the ground).
- To control tree ivy, cut the ivy stems at chest height all the way around the tree. Cut the ivy stems again at hip height, creating a gap on the trunk of the tree. Do not remove ivy stems from the canopy of the tree, as it can be dangerous and damaging to the tree and/or nesting birds. Canopy ivy may take a couple of months to die after the stems are cut.
- To control ground ivy, pull the plants, being careful to remove all of the roots. This is best done in winter when soil is moist and desirable vegetation is less likely to be damaged. Large infestations may require the careful use of an appropriate herbicide. Bag and dispose of removed plants as trash. Composting is not advised, as woody fragments can generate new growth after removal. If you have too much to bag, pile it onto a tarp, or on top of dead tree branches, to prevent re-rooting and allow it to die completely (may take many months). Monitor and turn pile to ensure it doesn’t re-root.
- For large infestations, chop through ivy roots in a line and then peel back the mat into a large roll. English ivy will re-grow from root fragments, so follow-up pulling will be needed.
- Monitor the site regularly and remove any new growth; vigilance is required to ensure long term control.
- Improper disposal of this plant is a primary cause of recurrent infestations.
- Home compost does not get hot enough to destroy plant fragments and seeds of invasive ivy. Bag seeds and place in trash.
- Monitor yard debris for escaped weeds.
- Never dump yard debris in natural areas.
- Only apply herbicides at proper rates and for the site conditions or land usage specified on the label. Follow all label directions and wear recommended personal protective equipment (PPE).
- Ivy in treated areas should not be mowed until after the herbicide has taken effect and weeds are brown and dead.
- Monitor treated areas for missed and newly germinated plants. To prevent re-introduction by birds, sites should be monitored yearly.
- Broadleaf selective herbicides are preferred over non-selective herbicides when applying in a grassy area.
- Minimize impacts to pollinators by controlling weeds before they flower. If possible, make herbicide applications in the morning or evening when bees are least active. Avoid spraying pollinators directly.
Specific Herbicide Information
Herbicides are described here by the active ingredient. Many commercial formulations are available containing specific active ingredients, but often are not formulated for use near aquatic sites. Always be sure to select an aquatically-approved herbicide and surfactant for use near water. References to product names are for example only. Directions for use may vary between brands.
- Glyphosate (e.g. Roundup), triclopyr [amine/salt; choline] (e.g. Garlon 3A, Vastlan), or a mix of glyphosate + triclopyr [amine/salt; choline] can be applied in late summer or during a sunny period in winter, ideally early- to mid-January, when temperatures are above 50 degrees, to reduce impacts to native species. Be sure to add the triclopyr to water before the glyphosate, to avoid incompatibility (which results in the clumping that plugs spray nozzles and can lead to ineffective treatments).
- An application of glyphosate + triclopyr can also be effective when applied to damaged foliar directly after string trimming.
- Ivy can take several months to die after an application.
- For larger infestations, the site should be replanted with the appropriate native vegetation to stabilize the soil surface.
- Recent trials in Portland found a 4-2-2 application method to be 95+% effective. This mix is 4% glyphosate, 2% triclopyr [amine/salt] (e.g. Garlon 3A), and 2% surfactant (e.g. Competitor). Be sure to mix triclopyr into solution with water prior to adding glyphosate or efficacy will be reduced. If using choline formulation of triclopyr (e.g Vastlan), reduce triclopyr percentage to 1.5% rate.
This BMP does not constitute a formal recommendation. When using herbicides, always consult the label.