English ivy (Hedera helix) may conjure up images of cozy, country cottages, but don’t be deceived. This invasive weed can destroy buildings, poison pets, and topple trees. The very characteristics that made it a popular ornamental plant – grows quickly, requires little maintenance, and provides a “no-mow,” evergreen ground cover — are the things that […]
English ivy (Hedera helix) may conjure up images of cozy, country cottages, but don’t be deceived. This invasive weed can destroy buildings, poison pets, and topple trees. The very characteristics that made it a popular ornamental plant – grows quickly, requires little maintenance, provides a “no-mow,” evergreen ground cover — are the things that have […]
English ivy (Hedera helix) may conjure up images of cozy, country cottages, but don’t be deceived. This invasive weed can destroy buildings, poison pets, and topple trees. The very characteristics that made it a popular ornamental plant – grows quickly, requires little maintenance, provides a “no-mow,” evergreen ground cover — are the things that have […]
English ivy (Hedera helix) may conjure up images of cozy, country cottages, but don’t be deceived. This invasive weed can destroy buildings, poison pets, and topple trees. The very characteristics that made it a popular ornamental plant – grows quickly, requires little maintenance, provides a “no-mow,” evergreen ground cover — are the things that have […]
English ivy (Hedera helix) may conjure up images of cozy, country cottages, but don’t be deceived. This invasive weed can destroy buildings, poison pets, and topple trees. The very characteristics that made it a popular ornamental plant – grows quickly, requires little maintenance, provides a “no-mow,” evergreen ground cover — are the things that have […]
English ivy (Hedera helix) may conjure up images of cozy, country cottages, but don’t be deceived. This invasive weed can destroy buildings, poison pets, and topple trees. The very characteristics that made it a popular ornamental plant – grows quickly, requires little maintenance, provides a “no-mow,” evergreen ground cover — are the things that have […]
English Ivy
Atlantic ivy or Irish ivy
Hedera helix (syns. Hedera helix ssp. helix, Hedera canariensis, Hedera helix ssp. canariensis)
Hedera hibernica (syns. Hedera helix ssp. hibernica)
English ivy is an evergreen climbing vine in the Araliaceae (Ginseng) family. It has historically been a common garden ornamental and has more than 400 cultivars. It has escaped cultivation to become highly invasive in forests and natural areas throughout the Pacific Northwest. Native to Europe, these plants are characterized by long viny stems reaching up to 30 m in length, with aerial, clinging small root. English ivy damages desirable vegetation by shading out and smothering plants. English ivy also covers trees making them more susceptible to wind fall due to the additional weight of the ivy in the trees as well as the additional drag of the evergreen leafy vines.
This vine climbs into the canopy of mature trees and so can grow very high.
Greenish-white
Typically blooming during months when not in a purely vegetative state.
In Oregon, three Hedera species have been documented: English ivy (H. helix), Atlantic ivy (H. hibernica), and Persian ivy (H. colchica). However, only English and Atlantic ivy are listed as noxious weeds in Oregon. The invasive plant commonly referred to as English ivy is actually comprised of both English ivy and Atlantic ivy. Identification and differentiation between the species is complicated because there many cultivated varieties. Both English ivy and Atlantic ivy have been commonly sold as English ivy, but can be differentiated by leaf shape and tiny hairs on the young leaves. These two species can also be differentiated through genetic testing.
The areas most infested by English ivy are urban natural areas, disturbed forests, woodlands, and along stream corridors. Plants grown in moist soils with summer shade and winter sunlight will flourish. Urban forest and natural areas are especially impacted as a result of repeated reinfestation from garden escapees.
Rapid and massive vegetative growth of English ivy vines reaches to treetops and woody ornamentals. It also can displace native vegetation on the forest floor. English ivy frequently becomes intertwined with forest shrubs creating difficulties for manual removal or herbicide use. Removal costs in some Oregon parks have reached $3000 per acre.
Europe
Oregon Noxious Weed Profile
Washington Noxious Weed Profile
King County Noxious Weed profile
CABI Invasive Species Compendium
The WeedWise Program has finalized Best Management Practices for controlling English ivy. Check out this comprehensive guide today.
English Ivy
Atlantic ivy or Irish ivy
Hedera helix (syns. Hedera helix ssp. helix, Hedera canariensis, Hedera helix ssp. canariensis)
Hedera hibernica (syns. Hedera helix ssp. hibernica)
English ivy is an evergreen climbing vine in the Araliaceae (Ginseng) family. It has historically been a common garden ornamental and has more than 400 cultivars. It has escaped cultivation to become highly invasive in forests and natural areas throughout the Pacific Northwest. Native to Europe, these plants are characterized by long viny stems reaching up to 30 m in length, with aerial, clinging small roots. English ivy damages desirable vegetation by shading out and smothering plants. English ivy also covers trees making them more susceptible to wind damage due to the additional weight of the ivy in the trees as well as the additional drag of the evergreen leafy vines. English ivy has two distinct growth forms: a juvenile form, that is characterized by rapid clonal and vegetative growth, and a mature form characterized by flowering and berry production.
In Oregon, three Hedera species have been documented: English ivy (H. helix), Atlantic ivy (H. hibernica), and Persian ivy (H. colchica). However, only H. helix and H. hibernica are listed as noxious weeds in Oregon. The invasive plant commonly referred to as English ivy is actually comprised of both H. helix and H. hibernica. Identification and differentiation between the species are complicated because of there many cultivated varieties. Both H. helix and H. hibernica have been commonly sold as English ivy, but can be differentiated by leaf shape and tiny hairs on the young leaves. These two species can also be differentiated through genetic testing.
The leaves come in two forms: juvenile and mature. Both leaves are evergreen, leathery, and palmately shaped. Juvenile leaves have 3-5 lobes and are slightly hairy. Generally, the lobes on H. helix are deeper than H. hibernica, but the lobes can vary. The leaves of mature ivy are ovate to diamond-shaped, unlobed or slightly lobed, darker green and more leathery. On both growth forms, the leaves alternate along the vines and are up to 10 cm long. Leaves can be toxic to humans and cattle if ingested. Leaves can also cause contact dermatitis in sensitive individuals.
English ivy generally will only flower under conditions with adequate light and optimal nutrients. Flowers are only produced high in the tree canopy within infested forests, or along steep slopes. English ivy flowers in the fall and are pollinated by insects. Adult plants flower in clusters. The flowers are five-petaled, greenish to white in coloration and are only 3-5 mm long.
Fruits develop as fleshy, dark blue to black berries that ripen in spring. Thousands of fruits can be produced by an adult plant each year. English ivy berries, particularly when underdeveloped, can be toxic to humans and cattle if ingested. These fruits are 5-10 mm in size and hold 1-3 seeds. Approximately 70% of the seeds produced are viable.
The juvenile English ivy plants have adventitious roots at their nodes. Roots are generally shallowly rooted, but robust. English ivy also forms aerial, clinging rootlets, allowing it to adhere and climb vertically. Adult English ivy plants form a woody base.
English ivy reproduces both from mature seeds as well as from root-like stems and sprouting fragments. The berries of English ivy are ingested by birds and the seeds can be dispersed great distances from parent plants. New plants can regenerate from stems and fragments from both the mature and juvenile growth forms. Regenerating plants maintain the growth form of their parents, such that plants formed from stem regeneration of adult form plants will keep adult characteristics. Once established juvenile plants can live up to 10 years before reaching maturation. English ivy plants can live up to 100 years or longer with one plant in England being documented at more than 400 years in age.
The areas most infested by English ivy are urban natural areas, disturbed forests, woodlands, and along stream corridors. Plants grown in moist soils with summer shade and winter sunlight will flourish. Urban forest and natural areas are especially impacted as a result of repeated reinfestation from garden escapees.
The original introduction of English ivy to the United States is believed to have been by European immigrants during colonial times as a garden ornamental. The earliest record of English ivy in North America dates to 1727. Introduction to the Portland area occurred between 1875 and 1899 (Christy et al., 2009).
The management of invasive weeds is best served through a process known as Integrated Pest Management (IPM). IPM is a weed management methodology that utilizes:
An IPM based strategy ensures the maximum effectiveness of treatment measures. IPM strategies typically use more than one management method to target one or more susceptible life stages. It should be adaptive to site conditions in the field and to the response of a plant to management. The utilization of multiple management tools inherently reduces the use of herbicides in a management plan. The IPM process ultimately provides a framework for the establishment of Best Management Practices (BMP) which outlines the best approach for controlling a weed particular infestation.
English ivy is often best controlled using manual control methods. The waxy leaves of English ivy and its ability to regenerate from stems and fragments, make it resistant to chemical and mechanical control methods. While effective the removal of English ivy can be time-consuming and labor-intensive. As such, persistence is possibly the most important factor in determining the success of your treatments. It has been suggested that an acre of English ivy dominated forest requires more than 300 man-hours for an initial clearing and continued maintenance to restore a site. So restoration efforts should plant their work accordingly
The first step is to choose an area, that can receive repeated control efforts. Prioritize your site. Choose a portion of your management area that is of highest priority, or work from a relatively intact area, and slowly expand your treatments systematically outward. Look at the concentration and location of the ivy, the landscape, soil moisture, abundance of native plants in the area as well as the number and skill of workers assisting. Before handling English ivy be sure to wear long sleeves, long pants, and gloves to protect yourself from potential dermatitis. Utilize tools such as shovels, rakes, mattocks, and weed wrenches to assist in the removal of the roots. Saws, loppers, and hand clippers can be used to cut vines.
In locations where native plants are abundant, the preferred practice is hand removal. Vines growing on trees should be targeted first to prevent flowering and seed set and to preserve canopy trees on site. Vines on trees should be cut using a saw, loppers or hand clippers around the entire base of the tree and also at a comfortable arm reach then removed from the tree. Leave the remaining ivy above the cut line to dry out and fall down on its own. All ivy should be removed within, a minimum of 3 feet around the trunk to better protect the tree. Flowering or seeding plants should be removed to prevent seeding or regeneration. For ground ivy control should focus on one location, pulling every vine and root up within reaching distance, before moving to a new location. Working systematically from a core area. Manual control of English ivy is best done in the fall and winter when the ground is soft and plants are not seeding.
When few native plants reside on the property and there are sufficient workers, English ivy can be removed in large mats using a technique called the ‘Log Roll’. This technique relies upon first defining a treatment area. The perimeter of the area is cut and a line of workers pull the edge of the mat, rolling vines and roots of the ivy on top of itself. It is important to shake the roots to remove soil. The roll should then be mulched in place to prevent resprouting. Workers should also follow up in the cleared site to remove any missed roots. This practice can be done on both flat ground and on hillsides. Soils with higher water content allow for an easier pull.
Additional tips to reduce erosion and minimize damage to native plants:
English ivy can be mowed or cut but this is generally not recommended due to its ability to regenerate following cutting.
Grazing has been used to defoliate large infestations of English ivy. Goats and sheep will graze the ivy leaves, but plants will readily resprout following grazing. As such, grazing animals must be rotated repeatedly back onsite to suppress regrowth. English ivy is generally not favored by grazing animals, so co-occurring native plants are usually grazed more strongly than the ivy itself. As such, grazing is generally considered to be ineffective, or of limited use. Mature ivy plants are also generally found growing above the browse line, so manual removal of tree ivy is required in conjunction with any grazing strategy.
English ivy is fire resistant and doesn’t carry a fire well. The repeated torching of ivy plants will cause cellular damage and dieback. With persistence, this method will exhaust nutrients as the English ivy resprouts, but it is generally inefficient compared to other methods. As such this method is generally not recommended.
Effective chemical control of English ivy is dependent on a few variables including timing, sensible application, and the proper mixture of chemicals. The timing is important to limit damage to native plants. Herbicide application during dry and sunny periods in late winter can be an effective chemical control on English ivy. The ivy is still alive and may still be growing in the winter while most native plants are dormant and protected. Herbicide has shown to be successful when applied directly to cut stems specifically around a tree trunk.
Foliar application of herbicides is deterred by the waxy coating on the leaves. This is especially true for older/mature leaves and application during the growing season. This leads to runoff of herbicide onto nearby native plants. A fatty acid can be applied before or with the herbicide application to increase absorption into the leaves.
Widespread chemical control of English ivy is not suggested and should only to be considered in areas completely dominated by ivy or on difficult sites were manual control methods may be impractical or dangerous.
Product Names: Accord, Aquamaster, Rodeo, Roundup, and various others
Rate:
Spot treat: use 2% to 5% v/v solution in water, with a non-ionic surfactant
Low volume/thin line: 10% v/v solutions in water.
Cut stump: 25% v/v solutions in water.
Time: Apply when actively growing in late summer early fall. An application can also be made on sunny winter days to avoid harming co-occurring natives. Cut stump applications should be made directly after cutting and during the dormant season for best results.
Comments: Wait four months after foliar treatment before cutting again. For cut stump application, cut stems horizontally or at ground level. Apply the solution directly after the cut. Treatment controls most resprouts. Glyphosate is not selective and will harm grasses. Use care when working around desirable plants to avoid damage. Leaves should be sprayed until wet but not dripping to achieve good control.
Product Names: Garlon 3A, Garlon 4 Ultra (triclopyr ester), Pathfinder II
Rate:
Spot treat: 2 to 5% v/v solution in water with a non-ionic surfactant.
Low volume/thin line: 10% v/v solution plus 20% basal oil concentrate in water.
Cut stump: 20% v/v solution in water.
Time: Apply post emergence in late summer to early fall, (August – October) when plants are growing rapidly. Cut stump applications should be made directly after a cut and during the dormant season for best results.
Comments: For cut stem treatment, follow the application description in Glyphosate. Triclopyr is selective and will harm desirable broad-leaf plants, trees, and shrubs. Use care when working around desirable plants to avoid damage. Leaves should be sprayed until wet but not dripping to achieve good control. Triclopyr ester formulations may volatilize under warm temperatures.
Product Names: Tordon 22K
Rate:
Broadcast: 3-4 pints/acre (0.75 to 1 lb a.e/acre) plus .25 to .5% v/v surfactant
Time: Apply postemergence in late summer to early fall, (August – October) when plants are growing rapidly at or beyond early to full bloom stage.
Comments: Picloram can have long-term soil activity and has shown to move with groundwater. It should not be used around trees because of root uptake. Use care when working around desirable plants to avoid damage. Leaves should be sprayed until wet but not dripping to achieve good control. Restricted herbicide.
Product Names: Arsenal, Habitat, Stalker, Chopper, Polaris
Rate:
Spot treat: 1 to 2% v/v solution plus .25 to .5% surfactant v/v in water.
Low volume/thin line: 10% v/v solution plus 20% ethylated crop oil in water.
Cut stump: 20% v/v solution in water plus 20% ethylated crop oil in water.
Time: Apply post emergence in late summer to early fall when the plant is growing rapidly.
Comments: Imazapyr exhibits some residual effects in the soil and may result in bare ground around plants after treatment. Care should be taken when replanting. Cut stump applications should be made directly after cutting and during the dormant season for best results.
Product Names: Tank Mixed
Rate:
Spot treat: 4% v/v Glyphosate solution + 2% v/v Triclopyr solution, with 1-2% non-ionic surfactant v/v in water.
Time: Apply in late summer with a late fall follow up.
Comments: Treat when temperatures are above 65 F when no rain is expected for 2-3 days.
There are no effective biological control agents available for English ivy.
There are many ways to dispose of English ivy when clearing your property. For small infestations, bagging up pulled plants is the best practice if possible. For larger infestations, pile up the debris and let it dry out. Placing a tarp under the pile will help prevent resprouting. Piles can also be covered to speed up drying and decompositions. Large debris piles can create dead spots, so placement of piles should be placed to minimize the impact to desirable vegetation. Under dry conditions, plants can be chopped into a mulch and spread over the area for ground cover and nutrients, but be careful with this method as covering the ground will reduce the visibility of missed/live roots.
Diligence is the most important aspect of controlling English Ivy. Ivy plants will readily resprout from any roots left remaining, so repeated follow-up is required. An herbicide application in summer has shown to be the most effective after treatment. Re-treatment may be required to achieve effective control. The seed may persist in the soil for years following treatment or arrive on-site from adjacent and nearby infestations.
