California Invasive Plant Council

Hedera helix

Common names: English ivy

Hedera helix (English ivy) is a perennial evergreen woody vine (family Araliaceae). It is found throughout California along the coast, as well as in Shasta and Butte Counties. English ivy grows vigorously in forests where nothing else seems able to compete and inhibits regeneration of understory plants, including forest wildflowers and new trees and shrubs. It is native to most of Europe and western Asia.

Cal-IPC Rating: High?

Explanation of Cal-IPC ratings

• High – These species have severe ecological impacts on physical processes, plant and animal communities, and vegetation structure. Their reproductive biology and other attributes are conducive to moderate to high rates of dispersal and establishment. Most are widely distributed ecologically.
• Moderate – These species have substantial and apparent-but generally not severe-ecological impacts on physical processes, plant and animal communities, and vegetation structure. Their reproductive biology and other attributes are conducive to moderate to high rates of dispersal, though establishment is generally dependent upon ecological disturbance. Ecological amplitude and distribution may range from limited to widespread.
• Limited – These species are invasive but their ecological impacts are minor on a statewide level or there was not enough information to justify a higher score. Their reproductive biology and other attributes result in low to moderate rates of invasiveness. Ecological amplitude and distribution are generally limited, but these species may be locally persistent and problematic.
• Alert – An Alert is listed on species with High or Moderate impacts that have limited distribution in California, but may have the potential to spread much further.
• Watch – These species have been assessed as posing a high risk of becoming invasive in the future in California.

CDFA Rating: None?

Explanation of CDFA ratings

• A – A pest of known economic or environmental detriment and is either not known to be established in California or it is present in a limited distribution that allows for the possibility of eradication or successful containment.
• B – A pest of known economic or environmental detriment and, if present in California, it is of limited distribution.
• C – A pest of known economic or environmental detriment and, if present in California, it is usually widespread.
• D – An organism known to be of little or no economic or environmental detriment, to have an extremely low likelihood of weediness, or is known to be a parasite or predator.
• Q – An organism or disorder suspected to be of economic or environmental detriment, but whose status is uncertain because of incomplete identification or inadequate information.
• * – An asterisk next to the rating indicates that a plant is included in the CCR Section 4500 list of California State Noxious Weeds.
• -* – This plant is included in the CCR Section 4500 list of California State Noxious Weeds, but is otherwise not rated.

More details

Assessment(s)

Hedera helix Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.

Weed Management Notes

• Management Notes - Information on management techniques and effectiveness from the University of California Cooperative Extension’s Weed Research & Information Center.

Cal-IPC Newsletter Articles

• Wildland Weed News. Cal-IPC. Vol 25, Issue 1
• Recommended action on invasive ornamentals. Cal-IPC. Vol 14, Issue 1
• Don’t sell a pest: A new partnership to prevent plant invasions through horticulture. Connick, Sarah; Gerel, Mike. Vol 13, Issue 2
• BLM uses heavy equipment to give weeds the heave-ho!. Wheeler, Jennifer. Vol 08, Issue 2
• Exotic pest plants of greatest ecological concern in California September 1994. Cal-IPC. Vol 02, Issue 4

Cal-IPC Symposium Presentations

Presentations are linked where available. Where a presentation is not available, find more information by reading the abstract in the Cal-IPC Symposia Archive.

• A case study on San Francisco’s most expensive weed, covering lessons, goals, and new methods to control it. Clark, Josiah (2024)
• The role of public gardens as sentinels of plant invasion. Culley, Theresa; Dreisilker, Kurt; Ryan, Clair; Landel, Hans; Cavallin, Nadia; Arcate Schuler, Jessica; Shultz, Brittany; Gettig, Roger; Havens, Kayri (2020)

Other Hedera helix Information

• Bugwood - National database from the Center for Invasive Species and Ecosystem Health at the University of Georgia.
• CalPhotos - Images of plants taken mostly in California.
• Calflora - Distribution map and records of this species in California.
• CalWeedMapper - Distribution map of this species in California with ability to determine regional priorities.
• EDDMapS - Distribution of this species in North America.
• Jepson Interchange - Information on this plant's taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
• USDA PLANTS Database - Information on identification and distribution, with links to websites in individual states.

Additional photos