Climate Matching Map
| Attachment | Size |
|---|---|
| climatematch-carex_pendula-washington-20251102.pdf (1.13 MB) | 1.13 MB |
1. Question 1
Yes
1
Very High
Carex pendula is native to Europe, western Asia, and northern Africa. Observations in western Washington (Washington State Noxious Weed Control Board. 2021), the Willamette Valley (Native Plant Society of Oregon 2008), California (Zika et al. 2015), and New Zealand (New Zealand Biosecurity 2020).
Board, Washington State Noxious Weed Control. 2020. “Draft Written Findings, Hanging Sedge (Carex Pendula)”. https://www.nwcb.wa.gov/pdfs/Carex_pendula_draft_Written_Findings_2020….
Zika, P.F. 2015. “Jepson EFlora: Carex Pendula”. Edited by A. L. Hipp. https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=80276.
Biosecurity, New Zealand. 2020. “National Pest Plant Accord”, 148 pp. doi:https://www.mpi.govt.nz/dmsdocument/3664-National-Pest-Plant-Accord-man….
Oregon, Native Plant Society of. 2008. “Exotic Gardening and Landscaping Plants Invasive in Native Habitats of the Southern Willamette Valley” 2021. https://emerald.npsoregon.org/inv_ornmtls.html.
2. Question 2
Yes
2
High
Carex pendula already occurs in Washington. The species' distribution in similar climates also includes California, Oregon, Tasmania, and New Zealand (PlantRight Climate Match [http://websites.greeninfo.org/images.tmp/6362f8e9fb4d215b8336d6846f4f4fee/Matching_Results.pdf], GBIF)
Secretariat, GBIF. 2021. “GBIF Backbone Taxonomy: Carex Pendula Huds”. https://www.gbif.org/species/2722051.
3. Question 3
Yes
2
High
Reports from Washington (Shaw 2020), California (Bikle 2014), and New Zealand (New Zealand Biosecurity 2020) describe an aggressive invader able to quickly occupy riparian and wetland habitats.
Shaw, S. 2020. “Hanging Sedge (Carex Pendula)”. Seattle, WA, 5 pp. https://www.nwcb.wa.gov/pdfs/Carex-pendula-information_King-County.pdf.
Bikle, Betsy Wanner. 2014. “It Takes a Village to Get Rid of an Invasive!”. Cal-IPC News 22: 4-5. www.cal-ipc.org.
Biosecurity, New Zealand. 2020. “National Pest Plant Accord”, 148 pp. doi:https://www.mpi.govt.nz/dmsdocument/3664-National-Pest-Plant-Accord-man….
4. Question 4
Yes
3
High
Reports from coastal California (Bikle 2014), and New Zealand (New Zealand Biosecurity 2020) describe invasions of riparian and wetland habitats in climates similar to western Washington (see also PlantRight Climate Match [http://websites.greeninfo.org/images.tmp/6362f8e9fb4d215b8336d6846f4f4fee/Matching_Results.pdf] and GBIF).
Bikle, Betsy Wanner. 2014. “It Takes a Village to Get Rid of an Invasive!”. Cal-IPC News 22: 4-5. www.cal-ipc.org.
Biosecurity, New Zealand. 2020. “National Pest Plant Accord”, 148 pp. doi:https://www.mpi.govt.nz/dmsdocument/3664-National-Pest-Plant-Accord-man….
Secretariat, GBIF. 2021. “GBIF Backbone Taxonomy: Carex Pendula Huds”. https://www.gbif.org/species/2722051.
5. Question 5
No
0
Medium
The genus Carex is globally very large, but the screener was unable to identify any Carexes known to be invasive in climates similar to the Pacific Northwest.
No references cited.
6. Question 6
Yes
2
Medium
Caerx pendula's global distribution is somewhat greater in similar climates such as California, Oregon, Europe and the British Isles, Tasmania, and New Zealand, although a significant portion of the species' distribution is in dissimilar climates, such as in Spain and the Mediterranean (PlantRight Climate Match [http://websites.greeninfo.org/images.tmp/6362f8e9fb4d215b8336d6846f4f4fee/Matching_Results.pdf], GBIF)
Secretariat, GBIF. 2021. “GBIF Backbone Taxonomy: Carex Pendula Huds”. https://www.gbif.org/species/2722051.
7. Question 7
Yes
1
High
Reports from Washington (Washington State Noxious Weed Control Board 2020), California (Bikle 2014), and New Zealand (New Zealand Biosecurity 2020) describe the species forming dense infestations in wetlands and riparian areas, displacing native vegetation.
Board, Washington State Noxious Weed Control. 2020. “Draft Written Findings, Hanging Sedge (Carex Pendula)”. https://www.nwcb.wa.gov/pdfs/Carex_pendula_draft_Written_Findings_2020….
Bikle, Betsy Wanner. 2014. “It Takes a Village to Get Rid of an Invasive!”. Cal-IPC News 22: 4-5. www.cal-ipc.org.
Biosecurity, New Zealand. 2020. “National Pest Plant Accord”, 148 pp. doi:https://www.mpi.govt.nz/dmsdocument/3664-National-Pest-Plant-Accord-man….
8. Question 8
No
0
Medium
Published information does not mention an impact on fire or fire regimes. The species’ primarily wetland and riparian habitats, though not fire-proof, are less fire-prone than upland areas.
No references cited.
9. Question 9
No
0
Very Low
Available literature provided no mention of risks to human, livestock, or wildlife health.
No references cited.
10. Question 10
No
0
Low
Plant is a cespitose perennial herb up to 2.0 m without armoring (Zika et al. 2015).
Zika, P.F. 2015. “Jepson EFlora: Carex Pendula”. Edited by A. L. Hipp. https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=80276.
11. Question 11
Yes
1
Medium
Zika et al. (2015) describe the specie as cespitose. However, the Weed Risk Assessment for Carex Pendula... (USDA 2013) lists rhizomes as a means of reproduction.
Zika, P.F. 2015. “Jepson EFlora: Carex Pendula”. Edited by A. L. Hipp. https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=80276.
APHIS, USDA. 2013. “Weed Risk Assessment for Carex Pendula Huds. (Cyperaceae) - Pendulous Sedge”. https://www.aphis.usda.gov/plant_health/plant_pest_info/weeds/downloads….
12. Question 12
No
0
Medium
A. Forrestel (cited in Brusati 2016) states that "reproduction from [rhizome] fragments is not a concern with this species."
Brusati, E. 2016. “Carex Pendula - California. Carex Pendula Risk Assessment”. https://www.cal-ipc.org/plants/risk/carex-pendula-risk/.
13. Question 13
Yes
1
Very High
Brandel (2005) and Schutz (2000) reported production of large numbers of seeds/ plant and high rates of germination in laboratory trials. Brandel and Schutz (2005) reported similar high rates of germination in field trials.
Schutz, W. 2000. “Ecology of Seed Dormancy and Germination in Sedges (Carex)”. Perspectives in Plant Ecology, Evolution and Systematics 3: 67-89.
Brändel, Markus. 2005. “The Effect of Stratification Temperatures on the Level of Dormancy in Primary and Secondary Dormant Seeds of Two Carex Species”. Plant Ecology 178: 163\textendash169. doi:10.1007/s11258-004-3037-y.
Brandel, M. 2005. “Temperature Effects on Dormancy Levels and Germination in Temperate Forest Sedges (Carex)”. Edited by W. Schutz. Plant Ecology 176:245-261 176: 245-61.
14. Question 14
Yes
1
Very High
Brandel and Schutz (2005) report production of 20,000 seeds/plant.
Brandel, M. 2005. “Temperature Effects on Dormancy Levels and Germination in Temperate Forest Sedges (Carex)”. Edited by W. Schutz. Plant Ecology 176:245-261 176: 245-61.
15. Question 15
Yes
1
Very High
Brandel (2005) and Schütz (2000) both reported germination of > 80% in laboratory and field trials. Dormancy in the species was broken by common overwinter field conditions (Brandel 2005).
No references cited.
16. Question 16
Yes
1
Medium
USDA-APHIS extrapolates from the species perennial habit and herbaceous growth form to suggest that reproductive maturity is likely within 3-5 years, but empirical information is lacking.
APHIS, USDA. 2013. “Weed Risk Assessment for Carex Pendula Huds. (Cyperaceae) - Pendulous Sedge”. https://www.aphis.usda.gov/plant_health/plant_pest_info/weeds/downloads….
17. Question 17
No
0
High
According to Zika et al. (2015) the fruiting period on the West Coast is limited to 3 months, April-June.
Zika, P.F. 2015. “Jepson EFlora: Carex Pendula”. Edited by A. L. Hipp. https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=80276.
18. Question 18
No
0
High
Seeds are primarily dispersed by water. USDA-APHIS 2013.
APHIS, USDA. 2013. “Weed Risk Assessment for Carex Pendula Huds. (Cyperaceae) - Pendulous Sedge”. https://www.aphis.usda.gov/plant_health/plant_pest_info/weeds/downloads….
19. Question 19
Yes
1
High
Seeds are dispersed primarily by water along streams, ditches, and in wetlands. USDA-APHIS 2013.
APHIS, USDA. 2013. “Weed Risk Assessment for Carex Pendula Huds. (Cyperaceae) - Pendulous Sedge”. https://www.aphis.usda.gov/plant_health/plant_pest_info/weeds/downloads….
20. Question 20
No
0
High
Natural dispersal of seeds is primarily by water. Although plants and seeds are dispersed deliberately via the horticultural trade, available information does not suggest any significant dispersal via contamination or other unintentional means (USDA-APHIS 2013).
APHIS, USDA. 2013. “Weed Risk Assessment for Carex Pendula Huds. (Cyperaceae) - Pendulous Sedge”. https://www.aphis.usda.gov/plant_health/plant_pest_info/weeds/downloads….
Evaluation Notes
New climate match map and link added + some references cleaned up for new web platform. New map has not been proofed against "yes" answer for Question 6. J. Burger 11/2/2025
Total PRE Score
17
20
73
