Climate Matching Map
| Attachment | Size |
|---|---|
| climatematch-iris_pseudacorus-united_states___nevada-20261025.pdf (1.48 MB) | 1.48 MB |
1. Question 1
Yes
1
High
Iris pseudacorus, from North Africa, Europe and Asia, was first documented escaping cultivation in 1911 (Bugwood Wiki, 2014). In 1961, Iris pseudacorus was reported to be naturalized in Canada, and it was established in California by 1957 and in Montana by 1958. It is now naturalized in parts of most states and provinces throughout North America except in the Rocky Mountains. (King County Department of Natural Resources and Parks Water and Land Resources Division, 2007).
“Yellow Flag Iris (Iris Pseudacorus) Ecological Risk Screening Summary”. 2019. www.fws.gov/sites/default/files/documents/Ecological-Risk-Screening-Sum….
“Iris Pseudacorus”. 2014. https://wiki.bugwood.org/Iris_pseudacorus.
“Yellow-Flag Iris (Iris Pseudacorus) Iridaceae”. 2007. https://your.kingcounty.gov/dnrp/library/archive-documents/wlr/LANDS/We….
2. Question 2
Yes
2
High
According to the climate map, this species has become naturalized in many states of the U.S., including states with similar climates to Nevada. Washington state, particularly eastern Washington, has reports of iris pseudacorus that match Nevada climates. According to the Washington noxious weed board, this species is a particular problem and is found growing along shores in shallow water where it was not planted (Washington State Noxious Weed Control Board, 2024). California also has reported this species as being naturalized in parts of the state, and it has similar climates to Nevada (California Invasive Plant Council, 2023).
“Yellow Flag Iris Iris Pseudacorus”. 2024. https://www.nwcb.wa.gov/weeds/yellow-flag-iris.
“Iris Pseudacorus”. 2023. https://www.cal-ipc.org/plants/profile/iris-pseudacorus-profile/.
3. Question 3
Yes
2
High
This species is considered highly invasive as its fast-growing, spreads rapidly, and outcompetes native vegetation (California Invasive Plant Council, 2023). The North Carolina Invasive Plant Council has listed this species as invasive as it threatens specifically wetlands by rapidly spreading and taking over (North Carolina Cooperative Extension, 2023). Washington state lists this species as a category C noxious weed (Washington State Noxious Weed Control Board, 2024) and B pest rating in California (California Invasive Plant Council, 2023). It is reported as invasive in these other states as well: Connecticut, Delaware, Maryland, New Hampshire, Oregon, Tennessee, Virginia, Vermont, Wisconsin, and West Virginia (U.S. Fish and Wildlife Service, 2019).
“Iris Pseudacorus”. 2023. https://www.cal-ipc.org/plants/profile/iris-pseudacorus-profile/.
“Iris Pseudacorus”. 2023. https://plants.ces.ncsu.edu/plants/iris-pseudacorus/.
“Yellow Flag Iris Iris Pseudacorus”. 2024. https://www.nwcb.wa.gov/weeds/yellow-flag-iris.
“Yellow Flag Iris (Iris Pseudacorus) Ecological Risk Screening Summary”. 2019. www.fws.gov/sites/default/files/documents/Ecological-Risk-Screening-Sum….
4. Question 4
Yes
3
High
Looking at the climate match tool, Washington state, California, and Oregon all have reports of this species being invasive and also have similar climates to Nevada (U.S. Fish and Wildlife Service, 2019)(California Invasive Plant Council, 2023)(Washington State Noxious Weed Control Board, 2024).
“Yellow Flag Iris (Iris Pseudacorus) Ecological Risk Screening Summary”. 2019. www.fws.gov/sites/default/files/documents/Ecological-Risk-Screening-Sum….
“Yellow Flag Iris Iris Pseudacorus”. 2024. https://www.nwcb.wa.gov/weeds/yellow-flag-iris.
“Iris Pseudacorus”. 2023. https://www.cal-ipc.org/plants/profile/iris-pseudacorus-profile/.
5. Question 5
No
0
Medium
There are no known species from the same genus as Iris pseudacorus that are invasive in similar climates to Nevada. Iris foetidissima is on the watch list in Washington state, meaning it may have the potential to become invasive, and it therefore being carefully monitored in the state (Washington State Noxious Weed Control Board, 2024). However, no other iris species have been considered invasive in similar climates at this time.
“Stinking Iris Iris Foetidissima”. 2024. https://www.nwcb.wa.gov/weeds/stinking-iris.
6. Question 6
No
0
High
Looking at the climate matching map, it is apparent that this species is not found in climates that predominately match the region of concern.
No references cited.
7. Question 7
Yes
1
Very High
This species can spread vegetatively through rhizomes and form dense stands that alter nature habitat as a result (gardenia.net, 2023). These stands can be compared to cattails where they form almost impenetrable thickets (California Invasive Plant Council, 2023). A peer reviewed study found that Iris pseudacorus helped with species richness and evenness in its native environment, but when it's an invader plant, it significantly reduced plant diversity of the native population (Gallego-Tévar, B., Grewell B. J., Whitcraft C. R., Futrell J. C., Bárcenas-Moreno G., & Castillo J. M., 2022).
“Native Plant Alternatives to Iris Pseudacorus (Yellow Iris)”. 2023. https://www.gardenia.net/guide/native-plant-alternatives-to-iris-pseuda….
“Iris Pseudacorus”. 2023. https://www.cal-ipc.org/plants/profile/iris-pseudacorus-profile/.
Gallego-Tévar, Blanca, Brenda J. Grewell, Christine R. Whitcraft, Joy C. Futrell, Gael Bárcenas-Moreno, and Jesús M. Castillo. (2022) 2022. “Contrasted Impacts of Yellow Flag Iris (Iris Pseudacorus) on Plant Diversity in Tidal Wetlands Within Its Native and Invaded Distribution Ranges”. Diversity 14: 1-16. doi:https://doi.org/10.3390/d14050326.
8. Question 8
No
0
Medium
There is no data currently that supports this species promotes fire and and is fire-adapted (USDA Forest Service Fire Effects Information System, 2023). It is assumed that fire would likely kill both Iris pseudacorus seedlings and mature plants. It is assumed that underground rhizomes might survive fires however.
“Iris Pseudacorus”. 2023. https://www.fs.usda.gov/database/feis/plants/forb/iripse/all.html.
9. Question 9
Yes
1
High
This species can harm livestock and other animals if ingested (King County, 2024). It also can cause skin irritations to humans when coming in contact with the resin. Overall, it is noted that herbivores typically avoid grazing this species due to all parts of the plants being toxic (USDA Forest Service, 2006).
“Yellow Flag Iris Identification and Control Iris Pseudacorus”. 2024. https://kingcounty.gov/en/legacy/services/environment/animals-and-plant….
“Yellow Iris Iris Pseudacorus L”. 2006. https://www.invasive.org/weedcd/pdfs/wow/yellow-iris.pdf.
10. Question 10
Yes
1
High
This species can form dense thickets or colonies in either fresh or brackish water that displace native plants and also alter the habitat for native animals (USDA Forest Service, 2006). There isn't literature available that states specifically that these thickets block or slow the movement of animals, but it can be inferred that these dense thickets would slow or prevent animals from accessing drinking water or crossing the body of water from one side to the other.
“Yellow Iris Iris Pseudacorus L”. 2006. https://www.invasive.org/weedcd/pdfs/wow/yellow-iris.pdf.
11. Question 11
Yes
1
High
This species can spread by rhizomes breaking (USDA Forest Service, 2006).
“Yellow Iris Iris Pseudacorus L”. 2006. https://www.invasive.org/weedcd/pdfs/wow/yellow-iris.pdf.
12. Question 12
Yes
1
High
The tuberous rhizomes spread rapidly each rhizome can produce up to 10 plants each. These large dense colonies are common and can have up to several hundred individual plants (NOAA Great Lakes Aquatic Nonindigenous Species Information System, 2018).
“Iris Pseudacorus L”. 2018. https://nas.er.usgs.gov/queries/greatlakes/FactSheet.aspx?Species_ID=11…\&Potential=N\&Type=0$\#$:~:text=Iris\%20pseudacorus\%20also\%20forms\%20thick,Je\%C2\%B4han\%20et\%20al.
13. Question 13
Yes
1
High
A study found that invasive Iris pseduacorus seeds remain viable after 55 days in saline water, despite typically needing water freshwater to germinate. (Gillard, M. B., Castillo J. M., Mesgaran M. B., Futrell C. J., & Grewell B. J., 2021). This study also found that other factors such as varying temperatures and daylight also did not significantly prevent this species from germinating. This shows that seed germination is a dependable method of reproduction, especially under invasive conditions, despite changing or varying environmental factors due to climate change.
“Yellow Flag Iris”. 2019. https://nyis.info/invasive_species/yellow-flag-iris/.
“Yellow Flag Iris Iris Pseudacorus L”. 2010. https://accs.uaa.alaska.edu/wp-content/uploads/Iris_pseudacorus_BIO_IRP….
Gillard, Morgane B., Jesús M. Castillo, Mohsen B. Mesgaran, Caryn J. Futrell, and Brenda J. Grewell. 2021. “High Aqueous Salinity Does Not Preclude Germination of Invasive Iris Pseudacorus from Estuarine Populations”. Ecosphere 12. doi:https://doi.org/10.1002/ecs2.3486.
14. Question 14
No
0
High
This species does produce up to several hundred seeds per plant, however, under 1,000 seeds per plant on average (New York Invasive Species Information, 2024). One study found that each plant produced 400-480 seeds per plant in Britain and between 150-240 seeds in Montana, and that they remained viable for up to a year (Alaska Natural Heritage Program, 2010).
“Yellow Flag Iris”. 2019. https://nyis.info/invasive_species/yellow-flag-iris/.
“Yellow Flag Iris Iris Pseudacorus L”. 2010. https://accs.uaa.alaska.edu/wp-content/uploads/Iris_pseudacorus_BIO_IRP….
15. Question 15
Yes
1
Very High
In certain field conditions this species has shown low germination rates with one source finding only around 20 percent success in the field of germination of seeds (Bugwood Wiki, 2014). However, other studies have found that germination from seeds is moderately successful. From a study in the British Isles, it was found that the seeds collected had a 48% germination rate (Morgan, V.H., Berent L., & Fusaro A., 2018). Seeds collected from a swamp in Florida were found to have a germination rate of 62%. In addition, a study found that seed germination rate was not negatively affected by changing factors such as light and temperature, or environmental stressors such as flooding (Gillard, M. B., Castillo J. M., Mesgaran M. B., Futrell C. J., & Grewell B. J., 2022). This suggests that this plant can germinate and thrive in a large variety of environmental conditions despite factors such as climate change impacting the ecosystem.
“Iris Pseudacorus”. 2014. https://wiki.bugwood.org/Iris_pseudacorus.
Gillard, Morgane B., Jesús M. Castillo, Mohsen B. Mesgaran, Caryn J. Futrell, and Brenda J. Grewell. 2022. “Germination Niche Breadth of Invasive Iris Pseudacorus (L.) Suggests Continued Recruitment from Seeds With Global Warming”. American Journal of Botany 2024. American Journal of Botany. doi:https://doi.org/10.1002/ajb2.16026.
Morgan, V.H, L. Berent, and A. Fusaro. 2018. “Iris Pseudacorus L”. https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=1115$\#$:~:text=Germination\%20from\%20seed\%20is\%20moderately,are\%20numerous\%20(Preece\%201964).
16. Question 16
No
0
High
This species requires at least 3 years of growth until it reaches maturity and is able to produce viable seed (NOAA Great Lakes Aquatic Nonindigenous Species Information System, 2018).
“Iris Pseudacorus L”. 2018. https://nas.er.usgs.gov/queries/greatlakes/FactSheet.aspx?Species_ID=11…\&Potential=N\&Type=0$\#$:~:text=Iris\%20pseudacorus\%20also\%20forms\%20thick,Je\%C2\%B4han\%20et\%20al.
17. Question 17
No
0
Very Low
The flowering period for this species is late spring to early summer typically, around April or May to June (Invasive Plant Atlas of the United States, 2018).
“Pale Yellow Iris, Yellow Flag Iris Iris Pseudacorus L”. 2018. https://www.invasiveplantatlas.org/subject.html?sub=5853.
18. Question 18
No
0
High
This species is toxic to animals and no species of birds are known to disperse the seeds of this species (Invasive Plant Atlas of the United States, 2018).
“Pale Yellow Iris, Yellow Flag Iris Iris Pseudacorus L”. 2018. https://www.invasiveplantatlas.org/subject.html?sub=5853.
19. Question 19
Yes
1
High
The seeds are light and buoyant and the mature plants are typically found near water, so the seeds can travel long distances (Invasive Plant Atlas of the United States, 2018, and USDA Forest Service Fire Effects Information System, 2023). The seeds will float down the shoreline and then germinate when the water recedes (U.S. Fish and Wildlife Service, 2019).
“Pale Yellow Iris, Yellow Flag Iris Iris Pseudacorus L”. 2018. https://www.invasiveplantatlas.org/subject.html?sub=5853.
“Iris Pseudacorus”. 2023. https://www.fs.usda.gov/database/feis/plants/forb/iripse/all.html.
“Yellow Flag Iris (Iris Pseudacorus) Ecological Risk Screening Summary”. 2019. www.fws.gov/sites/default/files/documents/Ecological-Risk-Screening-Sum….
20. Question 20
No
0
Medium
There is no literature found that suggests plant propagules are dispersed either directly or indirectly by humans. This species is found mostly in wetland areas where there might not be a lot of human traffic coming through. It is possible that the light seeds floating downstream (Invasive Plant Atlas of the United States, 2018) could be picked up by boats and transported to another location. One source states that this species has clogged drainage pipes and flood control ditches in urban settings. It's possible that this species could have gotten to these locations by human transportation (USDA Animal and Plant Health Inspection Service (APHIS), 2013).
“Pale Yellow Iris, Yellow Flag Iris Iris Pseudacorus L”. 2018. https://www.invasiveplantatlas.org/subject.html?sub=5853.
“Weed Risk Assessment for Iris Pseudacorus L. (Iridaceae) – Yellow Flag Iris”. 2013. www.aphis.usda.gov/plant_health/plant_pest_info/weeds/downloads/wra/Iri….
Evaluation Notes
The ClimateMatch version 2.0 was linked and attached after this PRE was moved to the new PREtool website. 10/24/2026- JB
Total PRE Score
16
20
76
