[SRM] FW: EDRR - poison hemlock and African rue

[Gornish, Elise - (egornish)]

Hi Everyone,

A couple of toxic plant EDRR updates to share:


  1.  It's come to my attention that there were a few reports of African rue (Peganum harmala) in southern Arizona in 2021/2022. This plant is both an AZ Noxious weed class A and a SDCWMA Class A invasive plant (ie highest priority for prevention). It looks like it is entering our area from NM where it was originally introduced to the US.
     *   As this is a prevention species, there is limited information on it in Arizona references. Here's some information I dug up from elsewhere. Of particular note is the high toxicity of the plant and the roots that reach 20ft in depth:

                                                    i.      EDDMapS invasive species profile<https://www.eddmaps.org/species/subject.cfm?sub=6158>

                                                   ii.     Texas Invasives profile<https://tsusinvasives.org/home/database/peganum-harmala>

     *   Locations. I realized that I had missed these reports previously because I had limited my notifications to Pima County. These are both in neighboring counties:

                                                    i.     There appear to be several reports in 2021/2022 in EDDMapS<https://www.eddmaps.org/tools/query/?observationDateEnd=06/18/2025&subjectnumber=6158&eradicationstatus=1,2&country=260,926&records=current> near Portal in a place labeled as Arizona Sky Village on the map;

                                                   ii.     iNaturalist also shows another report<https://www.inaturalist.org/observations?subview=map&taxon_id=78374> from 2021 near Eden off of US 70, NW of Safford.

     *   Requests:

                                                    i.     Does anyone have any contacts near these two locations that we can reach out to to share/confirm these reports? I haven't yet checked the land ownership status in these locations, but I'd imagine that anyone involved in invasive plant management nearby would be concerned and interested to receive this information, if they don't already know about the problem;

                                                   ii.     Does anyone have any experience removing this invasive plant? It looks like it would not be easy.



  1.  We have just released a large amount of iNaturalist data into EDDMapS and, in the process, I have realized that we have more poison hemlock (Conium maculatum) around Tucson than previously realized. There seem to be several infestations along the Santa Cruz in town, linked here<https://www.eddmaps.org/tools/query/?subjectnumber=4365&eradicationstatus=1,2&country=260,926&state=92604000&records=current>. This is not a state listed species, but it is on our CWMA EDRR Containment list. It is primarily an invasive plant of riparian areas, but EDDmapS indicates that we have at least 2 acres of it in and around town here in Tucson. I want to raise the profile of this species a bit so we can more actively monitor it and collect more accurate information on its extent going forward. If time permits, I will try to check out the report at Marshall Gulch on Mt Lemmon on our next EDRR event on Jul 1.
     *   References:

                                                    i.     EDDMapS invasive species profile<https://www.eddmaps.org/species/subject.cfm?sub=4365>

                                                   ii.     Nevada state noxious weed profile<https://agri.nv.gov/Plant/Noxious_Weeds/WeedList/Poison-hemlock_(Conium_maculatum)/>

     *   I have spoken to Ben Perry-Lemon about TBA's work removing poison hemlock in Tumacacori and it seems to have been a bit challenging. Is there anyone else in our group who has had personal experience doing poison hemlock removal?

Thanks again!

Ya-Ching Lin

GIS Analyst
Conservation, Education, and Science Department
Arizona-Sonora Desert Museum
2021 N Kinney Rd, Tucson, AZ 85743
+1 (520) 883-3023 w
+1 (520) 344-0666


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