California Invasive Plant Council

Volutaria tubuliflora

Synonyms: Amberboa atlantica; Volutaria lippii subsp. tubuliflora

Common names: desert knapweed; Mediterranean knapweed

Volutaria tubuliflora (desert knapweed) is an annual herb (family Asteraceae) with pink-purple flowers and lobed hairy leaves found in the desert ranges and south coast ranges of California. It is native to northern Africa and the Mediterranean Basin. It favors grasslands, dunes, scrub and chaparral habitat. It propagates via multitudes of seeds. Seeds are dispersed via human traffic, machinery, water and wind.

Learn more about the Cal-IPC project to contain desert knapweed.

Cal-IPC Rating: Limited — Alert?

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: A*?

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)

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

Cal-IPC Newsletter Articles

• Weeds on the Move. Cal-IPC. Vol 31, Issue 2
• Wildland Weed News. Cal-IPC. Vol 25, Issue 2
• Wildland Weed News. Cal-IPC. Vol 25, Issue 1
• Partnership aims to eradicate Volutaria tubuliflora. Robison, Ramona; Matthews, Pat; McDonald, Chris; Harris, Frank. Vol 25, Issue 1
• Early detection/rapid response around the state. Cal-IPC. Vol 23, Issue 2

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.

• Big Canyon Habitat Restoration and Resiliency Project Phase 3: CEQA exempt through CDFW’s SERP process. Arenas, Alys (2023)
• Regional EDRR with Bay Area WMAs. Johnson, Doug; Valentine, Nicole (2022)
• California Update. Johnson, Doug (2020)
• Containing and reducing the spread of Volutaria across southern California: Lessons learned when managing novel weed species. McDonald, Chris (2019)
• Successes, failures, and lessons from the Orange County CNPS Emergent Invasive Program. Vanderhoff, Ron (2019)
• Management of Volutaria tubuliflora at Anza-Borrego Desert State Park ̐ A community effort. Hyland, Mason (2017)
• Overcoming challenges: Managing the highly invasive Volutaria across California. McDonald, Chris (2017)
• Volutaria detection and management at Upper Newport Bay, Orange County. Vanderhoff, Ron (2017)
• 2016 Weed Alerts. Kelch, Dean (2016)
• Weed Alerts and CDFA Update. Kelch, Dean (2015)

Other Volutaria tubuliflora 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.

Additional photos