English & Irish Ivy
Hedera helix & Hedera hibernica
General: English and Irish Ivy are two species of evergreen, woody climbing vines. Ivy has two growth stages: a juvenile growth stage and a mature or reproductive growth stage. English and Irish Ivy typically remain in their juvenile growth stage for around 10 years and the plant must have sufficient sunlight to transition to its mature growth stage. Both growth stages may be found on the same plant.
Stem: Has purple-green stems that turn brown with age. In the juvenile stage, the stems of Ivy grow as a vine or groundcover. Juvenile stems also have rootlets, which produce an adhesive substance that allows them to cling to structures. In the mature growth stage, stems are thick and woody and either grow from the ground to form a shrub or climbs vertically up trees and other structures. Stems can grow up to 30 m long and 30 cm thick.
Leaves: Leaves are leathery to the touch, with a thick and waxy coating. Juvenile leaves have 3-5 lobes, alternate along the stem, and are typically dark green with distinct whitish veins. Mature leaves are unlobed, spirally arranged, and lighter green with a more rounded shape. English Ivy has erect hairs on the underside of its leaves, while Irish Ivy has flat hairs.
Flowers: English and Irish Ivy only produce flowers during their mature growth stage. The small, greenish-yellow flowers are arranged in distinct umbrella-like clusters.
Fruits: Like flowering, English and Irish Ivy only produce fruits and seeds during their mature growth stage. Fruits are round and bluish-black when ripe, and contain 2-5 stone-like seeds.
Habitat and Origin
Both English and Irish Ivy originate from Europe and were introduced to North America and many other temperate regions as a garden ornamental. It is a popular groundcover choice in the horticulture industry due to its fast-growing and low maintenance characteristics, as well as its tolerance to a variety of sunlight and soil conditions.
English and Irish Ivy can be found in a variety of habitats, such as disturbed areas, fields, parks, forest edges, coastal areas, and on steep slopes and cliffs. Its climbing vines can be spotted wrapped around trees, walls, houses, fences, posts, and hedges. Infestations are most often discovered in forested areas close to urban centres. While both species can grow in a range of environmental conditions and is shade tolerant in its juvenile growth stage, they do have a preference for direct sunlight with moist, well-drained soils. Sunlight is imperative for this species to transition to its mature growth stage.
Propagation & Vectors of Spread
English and Irish Ivy in their juvenile growth stage only spread vegetatively, while reproduction occurs through both vegetative means and seed propagation during the mature growth stage. In terms of vegetative propagation, these species can sprout new plants from any root or stem fragments that touch the soil, as well as its runners. Seeds are typically dispersed by birds that eat the fruits. English and Irish Ivy can be introduced to new regions by escaping gardens and sprouting from contaminated soil and fill material.
Ecological, Economic, & Health Impacts
- Forms ‘ivy deserts’ or dense monocultures, which threaten native plant communities and vegetation from the forest floor to the canopy.
- Overwhelms shrubs, trees, and seedlings by adding additional weight, as well as limiting photosynthesis and water intake.
- Carries Bacterial Leaf Scorch, which is a plant pathogen that infects tree species such as elms, oaks, and maples.
- Produces leaf litter that can even alter the nutrient contents of the soil.
- Causes serious damage to property and infrastructure.
- Damages built structures and cause trees to fall in storms and heavy winds.
- Dense patches of Ivy covering the ground offer habitat for rats and other vermin.
- Infestations of Ivy are extremely labour-intensive and costly to control. The Metro Vancouver regional government alone spends around $220,000 annually for the management of these species.
- The fruits and leaves of English and Irish Ivy are toxic to humans and livestock.
- Handling the plants may cause dermatitis and skin irritation for some people.
What Can I Do?
English & Irish Ivy are found in Squamish but not Whistler or Pemberton, so PREVENTION is key:
Learn to identify English and Irish Ivy: use the images presented in this profile page to learn how to identify English and Irish Ivy.
What to do if you spot it: You can report any English Ivy or Irish Ivy sighting by clicking here.
- Regularly monitor properties for weed infestations.
- Ensure soil and gravel are uncontaminated before transport.
- Minimize soil disturbances and use seed mixes with dense, early colonization (e.g. alfalfa or barley) to re-vegetate exposed soil and resist invasion.
- Ensure all plant parts are bagged or covered to prevent spread during transport to designated disposal sites.
- Unload, park or store equipment or vehicles in infested areas; remove plant material from any equipment, vehicles or clothing used in such areas and wash equipment and vehicles at designated cleaning sites before leaving infested areas.
- Plant English or Irish Ivy in a garden, no matter how well-contained its enclosure may seem.
- Compost any plant material. Instead, dispose of English and Irish Ivy in the general/household waste stream at the landfill as the plant parts will be able to persist the composting process.
- Move soil, gravel, or fill material that has been contaminated with English or Irish Ivy.
Mechanical control in the form of hand-pulling is the recommended method of removal for these species. Ensure that as much as possible of the root system is removed, as well as all plant fragments. Any stem or root fragment that touches the soil can sprout into a new plant. To hand-pull, grasp the vine and pull in the direction of growth. If the Ivy vine has climbed up a tree or other structure, first remove leaves and smaller vines to expose the larger vines attached to the structure. Cut the larger vines at shoulder and ankle height using pruning shears, saws, or a hand-axe to stop water and nutrient supply to the plant. If the vines are not embedded into the structure, pull them away with a flat pry bar or a long screwdriver. Ensure that all Ivy has been removed 1-2 m away from the base of the structure. Any Ivy left on the structure above shoulder height will eventually fall away.
Chemical control using glyphosate, metsulfuron-methyl, and triclopyr tends to be effective on young, actively growing plants but not as effective on mature plants. English and Irish Ivy are resistant to many pre-emergent pesticides, as the waxy texture of the leaves prevents absorption. Chemical control is often only recommended for large sites with dense growth and thick vines. All herbicide applications should be monitored over successive years as follow-up treatments may be required, and to evaluate the efficacy of the chemical control method.
We recommend that any herbicide application is carried out by a person holding a valid BC Pesticide Applicator Certificate. Before selecting and applying herbicides, you must review and follow herbicide labels and application rates; municipal, regional, provincial and federal laws and regulations; species-specific treatment recommendations, and site-specific goals and objectives.
- Global Invasive Species Database (GISD), http://www.iucngisd.org/gisd/species.php?sc=469
- Invasive Species Compendium, https://www.cabi.org/isc/datasheet/26694
- Invasive Plant Atlas, https://www.invasiveplantatlas.org/subject.html?sub=3027
- Invasive Species Council of BC (ISCBC), https://bcinvasives.ca/invasive-species/identify/invasive-plants/english-ivy
- Invasive Species Council of Metro Vancouver (ISCMV), http://www.metrovancouver.org/services/regional-planning/RPAC/invasive-species/RPACRegionalInvasiveSpeciesPublications/EnglishIrishIviesBMP.pdf
- Philadelphia Water Department, http://phillywatersheds.org/doc/9-Invasive%20Species_English%20Ivy.pdf
- Texas Invasive Species Institute, https://www.texasinvasives.org/plant_database/detail.php?symbol=HEHE
- USDA Forest Service, https://www.fs.fed.us/database/feis/plants/vine/hedhel/all.html