Known Locations and Status Updates


Select an invasive species from the list below to see the locations of known Orange County occurrences, as well as a status update from the chapter. Please do not report known Orange County occurrences. However, all new occurrences of these species should be documented and mapped to either Calflora (preferred) or iNaturalist. Alternatively, you may report these to  using the instructions at Reporting an Invasive Plant.

Status updates include information on new occurrences, management activities, updates about the population, successes and failures and other news regarding each invasive species.  If you have other updates or corrections, please report them for inclusion to .

For occasional  brief summaries of recent invasive plant information also see Invasive Updates.

2022 EMERGENT INVASIVE PLANT SPECIES IN ORANGE COUNTY

FORMER EMERGENT SPECIES

These species were previously Emergent Invasive in Orange County. They are no longer rated Emergent, but are still significant detection and management concerns. New detections should be documented on Calflora and/or iNaturalist.


SPECIES REVIEWED BUT REJECTED

These species have been carefully reviewed for consideration as an Emergent Invasive Plant in Orange County, but have been rejected. They will continue to be assessed annually. A rejection may be for various reasons:

  • Their distribution and abundance in the county have expanded past the Emergent level.
  • Although naturalized in the county, the species has not proven significantly invasive, and causing environmental disruption.
  • The occurrence(s) in the county are likely waifs and they have not been determined as persisting, naturalizing and being invasive.
  • The species is primarily aquatic.

Botanical Name

Common Name

Date Added

Score

Ageratina adenophora STICKY SNAKEROOT 2017 3.50
  Now well distributed in moist shaded drainages, coast to mountains.
Albizia lophantha STINK BEAN 2020 3.50
  Widely scattered locations. Ecological impacts appear to be low.
Commelina benghalensis DAYFLOWER 2018 3.50
  Often seen in weedy urban areas, But not significant or established in native vegetation.
Crassula colligata ssp. colligata AUSTRALIAN PYGMYWEED 2021 2.50
  First OC record in 2020. Environmental impacts not proven.
Dinebra retroflexa VIPER GRASS 2022 2.50
  A very small first OC detection in Irvine in 2021. Managed by OCCNPS and not re-found in future surveys. Waif status for now. 
Elymus ponticus TALL WHEAT GRASS 2021 1.50
  A single mature plant detected and removed in 2020 in Aliso-Wood Canyon Wilderness Park. Monitoring.
Erodium malacoides MEDITERRANEAN FILEREE 2018 2.75
  A handful of scatterred detections since 2016. Species is being monitored for environmental impacts.
Euphorbia segetalis GRAINFIELD SPURGE 2020 1.50
  A 1st OC confirmation in 2019 (nr. Trabuco Canyon) and another in 2022 (South Laguna). Being monitored.
Genista monspessulana FRENCH BROOM 2020 1.00
  A small population near cabins in Holy Jim Canyon is partially managed, but continuing. Monitoring for invasiveness.
Geranium molle CRANE'S BILL GERANIUM 2020 2.75
  Three OC observations, but not appearing invasive. More problematic to the North.
Geranium robertianum ROBERT'S GERANIUM 2020 2.75
  Apparently established at the Fullerton Arboretum, but nowhere else in the county.
Geranium rotundifolium ROUND LEAVED GERANIUM 2020 2.75
  A few records in urban edges dating to 2017, but not established in wildlands. 
Ipomoea cairica MILE-A-MINUTE VINE 2017 3.00
  Well established at several coastal locations, esp. along the South Coast and mostly in urban edge landscaping. Past Emergent.
Lathyrus tingitanus TANGIER PEA 2021 1.50
  Several colonies along SR74, in Riv. Co. A possible detection in Caspers Park and one confirmed in Silverado Cyn, both 2022. Being monitored.
Leucaena leucocephala WHITE LEADTREE 2020 3.00
  A significant invasive elsewhere. Here, primarily in riparian communities. Being monitored.
Limonium duriusculum SEA LAVENDER 2016 3.50
  Well distributed in the county and now well past the Emergent stage.
Limonium otolepis ASIAN SEA LAVENDER 2016 3.00
  A small clump rediscovered in 2021, following an old 1997 record. Managed immediately. Establishment uncertain.
Limonium preauxii SEA LAVENDER 2016 3.00
  Old records for Upper Newport Bay. Not relocated. Needs confirmation.
Limonium sventenii SEA LAVENDER 2016 3.00
  A 2008 record for Lake Forest. Not relocated. Needs confirmation of an extant population.
Liquidambar styraciflua SWEETGUM 2017 3.00
  Occasional waifs, but not confirmed as an environmental threat.
Pallenis maritima GOLD COIN 2022 3.00
  Small patches are established at scatterred locations on ocean-facing bluffs, but not determined as having environmental impacts.
Parietaria judaica SPREADING PELLITORY 2021 2.75
  A recent urban weed primarily  in the Huntington and Sunset Beach areas. Not yet detected in wildlands.
Parthenocissus inserta WOODBINE 2021 3.00
  Silverado and Irvine colonies are being monitored.
Paspalum vaginatum SEASHORE PASPALUM 2017 2.25
  A significant invasive, but now well established at many freshwater/brackish water locations.
Pelargonium grossularioides GOOSEBERRY PELARGONIUM 2021 3.00
  Scatterred plants and small colonies, but it's ability to invade wildlands is not established, nor its environmental impacts.
Pennisetum villosum FEATHERTOP 2017 2.50
  Scatterred around the county, but not proven strongly aggressive or disruptive.
Phytolacca americana AMERICAN POKEWEED 2021 3.25
  A few recent records (>2019) but at ruderal urban areas. Not appearing as a wildland's invader.
Phytolacca icosandra TROPICAL POKEWEED 2021 2.50
  Also a few records >2017, but all in urban areas or ruderal waste areas. Not establishing in wildland's.
Pistia stratiotes (aquatic) WATER LETTUCE 2018 1.50
  Aquatic plants are not included in the final OCCNPS Emergent Invasive Plant List.
Plantago arenaria INDIAN PLANTAIN 2017 2.00
  Common at the Bolsa Chica Ecological and other coastal wetlands. Past the Emergent stage.
Plecostachys serpyllifolia PETITE LICORICE 2017 2.25
  Occasional patches along coastal bluffs and coastal canyons. Monitoring.
Ranunculus arvensis FIELD BUTTERCUP 2017 2.50
  Two collections from 2000 have not been re-observed. Assumed extirpated.
Ranunculus muricatus BUTTERCUP 2021 2.75
  Two small patches in urban, irrigated landscaping only.
Rapistrum ragosum TURNIPWEED 2021 1.00
  Ladd Cyn (2019) and Upper Newport Bay (2020) detections. Monitoring. 
Salvinia minima (aquatic) WATER SPANGLES 2021 1.00
  Aquatic plants are not included in the final OCCNPS Emergent Invasive Plant List.
Salvinia molesta (aquatic) KARIBA WEED 2017 1.00
  Aquatic plants are not included in the final OCCPS Emergent Invasive Plant List.
Senna didymobotrya AFRICAN WILD CASSIA 2017 2.25
  Plants and small colonies are scatterred through the lowlands. Not yet determined as a wildland invasive and likely past Emergent.
Sesbania punicea RATTLEBOX 2021 1.25
  A single plant was rediscovered and removed at Upper Newport Bay in 2020, following a 2006 detection. Waifs, not considered established.
Solanum aviculare (laciniatum?) NEW ZEALAND NIGHTSHADE 2017 2.50
  Taxonomy is confused, may be conspecific. A colony persists in Hunt. Central Park, but invasiveness is not certain.
Tamarix aphylla ATHEL TAMARISK 2021 2.75
  Small colonies in Black Star Cyn. and near Rancho Santa Margarita are concerning. Monitoring.
Triadica sebifera CHINESE TALLOWTREE 2017 1.50
  Populations, esp. in San Clemente and Orange are being monitored. Not in wildlands.

Known Locations and Status Updates

Select an invasive species from the list below to see the locations of known Orange County occurrences, as well as a status update from the chapter. Please do not report known Orange County occurrences. However, all new occurrences of these species should be documented and mapped to either Calflora (preferred) or iNaturalist. Alternatively, you may report these to  using the instructions at Reporting an Invasive Plant.

Status updates include information on new occurrences, management activities, updates about the population, successes and failures and other news regarding each invasive species.  If you have other updates or corrections, please report them for inclusion to .

For occasional  brief summaries of recent invasive plant information also see Invasive Updates.

2022 EMERGENT INVASIVE PLANT SPECIES IN ORANGE COUNTY

FORMER EMERGENT SPECIES

These species were previously Emergent Invasive in Orange County. They are no longer rated Emergent, but are still significant detection and management concerns. New detections should be documented on Calflora and/or iNaturalist.


SPECIES REVIEWED BUT REJECTED

These species have been carefully reviewed for consideration as an Emergent Invasive Plant in Orange County, but have been rejected. They will continue to be assessed annually. A rejection may be for various reasons:

  • Their distribution and abundance in the county have expanded past the Emergent level.
  • Although naturalized in the county, the species has not proven significantly invasive, and causing environmental disruption.
  • The occurrence(s) in the county are likely waifs and they have not been determined as persisting, naturalizing and being invasive.
  • The species is primarily aquatic.

Botanical Name

Common Name

Date Added

Score

Ageratina adenophora STICKY SNAKEROOT 2017 3.50
  Now well distributed in moist shaded drainages, coast to mountains.
Albizia lophantha STINK BEAN 2020 3.50
  Widely scattered locations. Ecological impacts appear to be low.
Commelina benghalensis DAYFLOWER 2018 3.50
  Often seen in weedy urban areas, But not significant or established in native vegetation.
Crassula colligata ssp. colligata AUSTRALIAN PYGMYWEED 2021 2.50
  First OC record in 2020. Environmental impacts not proven.
Dinebra retroflexa VIPER GRASS 2022 2.50
  A very small first OC detection in Irvine in 2021. Managed by OCCNPS and not re-found in future surveys. Waif status for now. 
Elymus ponticus TALL WHEAT GRASS 2021 1.50
  A single mature plant detected and removed in 2020 in Aliso-Wood Canyon Wilderness Park. Monitoring.
Erodium malacoides MEDITERRANEAN FILEREE 2018 2.75
  A handful of scatterred detections since 2016. Species is being monitored for environmental impacts.
Euphorbia segetalis GRAINFIELD SPURGE 2020 1.50
  A 1st OC confirmation in 2019 (nr. Trabuco Canyon) and another in 2022 (South Laguna). Being monitored.
Genista monspessulana FRENCH BROOM 2020 1.00
  A small population near cabins in Holy Jim Canyon is partially managed, but continuing. Monitoring for invasiveness.
Geranium molle CRANE'S BILL GERANIUM 2020 2.75
  Three OC observations, but not appearing invasive. More problematic to the North.
Geranium robertianum ROBERT'S GERANIUM 2020 2.75
  Apparently established at the Fullerton Arboretum, but nowhere else in the county.
Geranium rotundifolium ROUND LEAVED GERANIUM 2020 2.75
  A few records in urban edges dating to 2017, but not established in wildlands. 
Ipomoea cairica MILE-A-MINUTE VINE 2017 3.00
  Well established at several coastal locations, esp. along the South Coast and mostly in urban edge landscaping. Past Emergent.
Lathyrus tingitanus TANGIER PEA 2021 1.50
  Several colonies along SR74, in Riv. Co. A possible detection in Caspers Park and one confirmed in Silverado Cyn, both 2022. Being monitored.
Leucaena leucocephala WHITE LEADTREE 2020 3.00
  A significant invasive elsewhere. Here, primarily in riparian communities. Being monitored.
Limonium duriusculum SEA LAVENDER 2016 3.50
  Well distributed in the county and now well past the Emergent stage.
Limonium otolepis ASIAN SEA LAVENDER 2016 3.00
  A small clump rediscovered in 2021, following an old 1997 record. Managed immediately. Establishment uncertain.
Limonium preauxii SEA LAVENDER 2016 3.00
  Old records for Upper Newport Bay. Not relocated. Needs confirmation.
Limonium sventenii SEA LAVENDER 2016 3.00
  A 2008 record for Lake Forest. Not relocated. Needs confirmation of an extant population.
Liquidambar styraciflua SWEETGUM 2017 3.00
  Occasional waifs, but not confirmed as an environmental threat.
Pallenis maritima GOLD COIN 2022 3.00
  Small patches are established at scatterred locations on ocean-facing bluffs, but not determined as having environmental impacts.
Parietaria judaica SPREADING PELLITORY 2021 2.75
  A recent urban weed primarily  in the Huntington and Sunset Beach areas. Not yet detected in wildlands.
Parthenocissus inserta WOODBINE 2021 3.00
  Silverado and Irvine colonies are being monitored.
Paspalum vaginatum SEASHORE PASPALUM 2017 2.25
  A significant invasive, but now well established at many freshwater/brackish water locations.
Pelargonium grossularioides GOOSEBERRY PELARGONIUM 2021 3.00
  Scatterred plants and small colonies, but it's ability to invade wildlands is not established, nor its environmental impacts.
Pennisetum villosum FEATHERTOP 2017 2.50
  Scatterred around the county, but not proven strongly aggressive or disruptive.
Phytolacca americana AMERICAN POKEWEED 2021 3.25
  A few recent records (>2019) but at ruderal urban areas. Not appearing as a wildland's invader.
Phytolacca icosandra TROPICAL POKEWEED 2021 2.50
  Also a few records >2017, but all in urban areas or ruderal waste areas. Not establishing in wildland's.
Pistia stratiotes (aquatic) WATER LETTUCE 2018 1.50
  Aquatic plants are not included in the final OCCNPS Emergent Invasive Plant List.
Plantago arenaria INDIAN PLANTAIN 2017 2.00
  Common at the Bolsa Chica Ecological and other coastal wetlands. Past the Emergent stage.
Plecostachys serpyllifolia PETITE LICORICE 2017 2.25
  Occasional patches along coastal bluffs and coastal canyons. Monitoring.
Ranunculus arvensis FIELD BUTTERCUP 2017 2.50
  Two collections from 2000 have not been re-observed. Assumed extirpated.
Ranunculus muricatus BUTTERCUP 2021 2.75
  Two small patches in urban, irrigated landscaping only.
Rapistrum ragosum TURNIPWEED 2021 1.00
  Ladd Cyn (2019) and Upper Newport Bay (2020) detections. Monitoring. 
Salvinia minima (aquatic) WATER SPANGLES 2021 1.00
  Aquatic plants are not included in the final OCCNPS Emergent Invasive Plant List.
Salvinia molesta (aquatic) KARIBA WEED 2017 1.00
  Aquatic plants are not included in the final OCCPS Emergent Invasive Plant List.
Senna didymobotrya AFRICAN WILD CASSIA 2017 2.25
  Plants and small colonies are scatterred through the lowlands. Not yet determined as a wildland invasive and likely past Emergent.
Sesbania punicea RATTLEBOX 2021 1.25
  A single plant was rediscovered and removed at Upper Newport Bay in 2020, following a 2006 detection. Waifs, not considered established.
Solanum aviculare (laciniatum?) NEW ZEALAND NIGHTSHADE 2017 2.50
  Taxonomy is confused, may be conspecific. A colony persists in Hunt. Central Park, but invasiveness is not certain.
Tamarix aphylla ATHEL TAMARISK 2021 2.75
  Small colonies in Black Star Cyn. and near Rancho Santa Margarita are concerning. Monitoring.
Triadica sebifera CHINESE TALLOWTREE 2017 1.50
  Populations, esp. in San Clemente and Orange are being monitored. Not in wildlands.


Select an invasive species from the list below to see the locations of known Orange County occurrences, as well as a status update from the chapter. Please do not report known Orange County occurrences. However, all new occurrences of these species should be documented and mapped to either Calflora (preferred) or iNaturalist. Alternatively, you may report these to  using the instructions at Reporting an Invasive Plant.

Status updates include information on new occurrences, management activities, updates about the population, successes and failures and other news regarding each invasive species.  If you have other updates or corrections, please report them for inclusion to .

For occasional  brief summaries of recent invasive plant information also see Invasive Updates.

2022 EMERGENT INVASIVE PLANT SPECIES IN ORANGE COUNTY

FORMER EMERGENT SPECIES

These species were previously Emergent Invasive in Orange County. They are no longer rated Emergent, but are still significant detection and management concerns. New detections should be documented on Calflora and/or iNaturalist.


SPECIES REVIEWED BUT REJECTED

These species have been carefully reviewed for consideration as an Emergent Invasive Plant in Orange County, but have been rejected. They will continue to be assessed annually. A rejection may be for various reasons:

  • Their distribution and abundance in the county have expanded past the Emergent level.
  • Although naturalized in the county, the species has not proven significantly invasive, and causing environmental disruption.
  • The occurrence(s) in the county are likely waifs and they have not been determined as persisting, naturalizing and being invasive.
  • The species is primarily aquatic.

Botanical Name

Common Name

Date Added

Score

Ageratina adenophora STICKY SNAKEROOT 2017 3.50
  Now well distributed in moist shaded drainages, coast to mountains.
Albizia lophantha STINK BEAN 2020 3.50
  Widely scattered locations. Ecological impacts appear to be low.
Commelina benghalensis DAYFLOWER 2018 3.50
  Often seen in weedy urban areas, But not significant or established in native vegetation.
Crassula colligata ssp. colligata AUSTRALIAN PYGMYWEED 2021 2.50
  First OC record in 2020. Environmental impacts not proven.
Dinebra retroflexa VIPER GRASS 2022 2.50
  A very small first OC detection in Irvine in 2021. Managed by OCCNPS and not re-found in future surveys. Waif status for now. 
Elymus ponticus TALL WHEAT GRASS 2021 1.50
  A single mature plant detected and removed in 2020 in Aliso-Wood Canyon Wilderness Park. Monitoring.
Erodium malacoides MEDITERRANEAN FILEREE 2018 2.75
  A handful of scatterred detections since 2016. Species is being monitored for environmental impacts.
Euphorbia segetalis GRAINFIELD SPURGE 2020 1.50
  A 1st OC confirmation in 2019 (nr. Trabuco Canyon) and another in 2022 (South Laguna). Being monitored.
Genista monspessulana FRENCH BROOM 2020 1.00
  A small population near cabins in Holy Jim Canyon is partially managed, but continuing. Monitoring for invasiveness.
Geranium molle CRANE'S BILL GERANIUM 2020 2.75
  Three OC observations, but not appearing invasive. More problematic to the North.
Geranium robertianum ROBERT'S GERANIUM 2020 2.75
  Apparently established at the Fullerton Arboretum, but nowhere else in the county.
Geranium rotundifolium ROUND LEAVED GERANIUM 2020 2.75
  A few records in urban edges dating to 2017, but not established in wildlands. 
Ipomoea cairica MILE-A-MINUTE VINE 2017 3.00
  Well established at several coastal locations, esp. along the South Coast and mostly in urban edge landscaping. Past Emergent.
Lathyrus tingitanus TANGIER PEA 2021 1.50
  Several colonies along SR74, in Riv. Co. A possible detection in Caspers Park and one confirmed in Silverado Cyn, both 2022. Being monitored.
Leucaena leucocephala WHITE LEADTREE 2020 3.00
  A significant invasive elsewhere. Here, primarily in riparian communities. Being monitored.
Limonium duriusculum SEA LAVENDER 2016 3.50
  Well distributed in the county and now well past the Emergent stage.
Limonium otolepis ASIAN SEA LAVENDER 2016 3.00
  A small clump rediscovered in 2021, following an old 1997 record. Managed immediately. Establishment uncertain.
Limonium preauxii SEA LAVENDER 2016 3.00
  Old records for Upper Newport Bay. Not relocated. Needs confirmation.
Limonium sventenii SEA LAVENDER 2016 3.00
  A 2008 record for Lake Forest. Not relocated. Needs confirmation of an extant population.
Liquidambar styraciflua SWEETGUM 2017 3.00
  Occasional waifs, but not confirmed as an environmental threat.
Pallenis maritima GOLD COIN 2022 3.00
  Small patches are established at scatterred locations on ocean-facing bluffs, but not determined as having environmental impacts.
Parietaria judaica SPREADING PELLITORY 2021 2.75
  A recent urban weed primarily  in the Huntington and Sunset Beach areas. Not yet detected in wildlands.
Parthenocissus inserta WOODBINE 2021 3.00
  Silverado and Irvine colonies are being monitored.
Paspalum vaginatum SEASHORE PASPALUM 2017 2.25
  A significant invasive, but now well established at many freshwater/brackish water locations.
Pelargonium grossularioides GOOSEBERRY PELARGONIUM 2021 3.00
  Scatterred plants and small colonies, but it's ability to invade wildlands is not established, nor its environmental impacts.
Pennisetum villosum FEATHERTOP 2017 2.50
  Scatterred around the county, but not proven strongly aggressive or disruptive.
Phytolacca americana AMERICAN POKEWEED 2021 3.25
  A few recent records (>2019) but at ruderal urban areas. Not appearing as a wildland's invader.
Phytolacca icosandra TROPICAL POKEWEED 2021 2.50
  Also a few records >2017, but all in urban areas or ruderal waste areas. Not establishing in wildland's.
Pistia stratiotes (aquatic) WATER LETTUCE 2018 1.50
  Aquatic plants are not included in the final OCCNPS Emergent Invasive Plant List.
Plantago arenaria INDIAN PLANTAIN 2017 2.00
  Common at the Bolsa Chica Ecological and other coastal wetlands. Past the Emergent stage.
Plecostachys serpyllifolia PETITE LICORICE 2017 2.25
  Occasional patches along coastal bluffs and coastal canyons. Monitoring.
Ranunculus arvensis FIELD BUTTERCUP 2017 2.50
  Two collections from 2000 have not been re-observed. Assumed extirpated.
Ranunculus muricatus BUTTERCUP 2021 2.75
  Two small patches in urban, irrigated landscaping only.
Rapistrum ragosum TURNIPWEED 2021 1.00
  Ladd Cyn (2019) and Upper Newport Bay (2020) detections. Monitoring. 
Salvinia minima (aquatic) WATER SPANGLES 2021 1.00
  Aquatic plants are not included in the final OCCNPS Emergent Invasive Plant List.
Salvinia molesta (aquatic) KARIBA WEED 2017 1.00
  Aquatic plants are not included in the final OCCPS Emergent Invasive Plant List.
Senna didymobotrya AFRICAN WILD CASSIA 2017 2.25
  Plants and small colonies are scatterred through the lowlands. Not yet determined as a wildland invasive and likely past Emergent.
Sesbania punicea RATTLEBOX 2021 1.25
  A single plant was rediscovered and removed at Upper Newport Bay in 2020, following a 2006 detection. Waifs, not considered established.
Solanum aviculare (laciniatum?) NEW ZEALAND NIGHTSHADE 2017 2.50
  Taxonomy is confused, may be conspecific. A colony persists in Hunt. Central Park, but invasiveness is not certain.
Tamarix aphylla ATHEL TAMARISK 2021 2.75
  Small colonies in Black Star Cyn. and near Rancho Santa Margarita are concerning. Monitoring.
Triadica sebifera CHINESE TALLOWTREE 2017 1.50
  Populations, esp. in San Clemente and Orange are being monitored. Not in wildlands.