Emergent Invasive Plant Program

“Emergent” invasive plants are specific non-native species that have appeared recently in OC, are not yet widely distributed here, and are known or presumed to spread readily and cause significant environmental harm. 
  • They are of particular concern because they pose unknown or likely future competition for our native flora.
  • They are of particular priority because, as their populations are still small, they have the greatest potential to be effectively controlled or even eradicated.

OC-CNPS members can assist in resolving these challenges by providing Early Detection and Rapid Response:

  • Trained “eyes on the ground” to report new populations of priority emergent weed species.
  • Facilitation of land managers, land owners and potential labor forces for response and control, both within and across boundaries.
  • Engagement with other volunteer organizations to assist with priority weed populations that may otherwise not be managed.


Join us! Contact us at: invasives@occnps.org

  • report a new site of an Emergent Invasive Species or a new weed in Orange County.
  • tackle an invasive plant site infestation.
  • provide follow-up monitoring of areas of emergent invasive plant populations.
  • adopt a trail or area to search for and report new invasions.
  • help with outreach, communications, land managers, lots more.
  • receive our occasional Emergent Invasive email updates.


OC-CNPS’ Emergent Invasives Committee has developed a list of emergent weeds to guide Chapter members.
  • The list is dynamic, changing as emergent populations become known and controlled and new ones are found.
  • It contains a manageable number of emergent weeds.
  • It may contain:
  • Species that OC-CNPS has given top priority due to their local distribution, invasiveness, and ability to negatively impact native habitat.
  • Other locally occurring priority species that will be evaluated regularly.
  • Potentially invasive species with unknown status.
  • New potential invaders that have not yet been observed in Orange County.
By becoming familiar with these emergent weeds, and accurately identifying and reporting their occurrences, you can make a significant contribution to the protection of OC’s natural areas from invasive plants.

Each species’ known OC locations are listed in Known Locations & Status Updates.  If you find one in a new location, please see Reporting an Invasive Plant and immediately report your find to invasives@occnps.org.

OC-CNPS also:

  • Leads Invasive Plant Training Classes. Intensive Early Detection training is available for land managers, land stewards, agencies, volunbteers, NGO’s, and other intersted parties.
  • Assists with ongoing treatment activities at specific sites throughout Orange County. These include both emergent invasives and other non-native invasive plants.
  • Recognizes that a number of other weed species are high priorities regionally, but that its own capacity to deal with those wide-spread, common weeds is limited.

OC-CNPS Early Detection Training:

Orange County CNPS training for early
detection of high priority non-native invasive plants

Focused training for volunteers, land managers, stewardship groups, agency staff and others

Extensive classroom instruction by CNPS experts, with optional Calflora training

Detailed identification of Orange County’s highest priority invasive plant species


More information is available here or send inquiries to invasives@OCCNPS.org.

Additional resources:

  • See the PowerPoint presentation presented by OC CNPS at the Oct. 2015 Cal-IPC Annual Symposium here.
  • See the handout from the Invasive Plant Mapping Workshop conducted on July 7, 2016 here.

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