2024 OC Emergent Invasive Plants

This list represents the 2024 prioritization of the newest and potentially most environmentally disruptive non-native plant species in Orange County. This list is specific to non-native, naturalized plant species in Orange County, with very small populations, which also have a high probability of causing significant environmental damage and loss of biodiversity. These species are small enough populations, where complete control and extirpation is still feasible.
New detections, updates, or corrections should be reported to invasives@occnps.org.
For information about the methodology for scoring, candidate species, and change highlights, read the “Emergent Invasive Plants in Orange County – A 2024 Update and Priority List” by Ron Vanderhoff.

 


 

THE 2024 OC EMERGENT INVASIVE PLANT LIST

 

Genista monspessulana FRENCH BROOM

OCCNPS Invasive Score:  1.00
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon ReportCAL-IPC Profile

 

Brassica fruticulosa – MEDITERRANEAN CABBAGE

OCCNPS Invasive Score:  1.14
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon Report

 

Galenia pubescens COASTAL GALENIA

OCCNPS Invasive Score:  1.31
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon Report

 

Cenchrus longispinus MAT SANDBUR

OCCNPS Invasive Score:  1.64
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon ReportCAL-IPC Profile

 

Osteospermum calendulaceum STINKING ROGER

OCCNPS Invasive Score:  1.64
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon Report

 

Cenchrus echinatus SOUTHERN SANDBUR

OCCNPS Invasive Score:  1.71
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon ReportCAL-IPC Profile

 

Volutaria tubuliflora EGYPTIAN KNAPWEED

OCCNPS Invasive Score:  1.86
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon ReportCAL-IPC Profile

 

Chrysanthemoides monilifera ssp. monilifera BITOU BUSH

OCCNPS Invasive Score:  2.00
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon ReportCAL-IPC Profile

 

Hypericum canariense CANARY ISLAND ST. JOHN’S WORT

OCCNPS Invasive Score:  2.36
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon ReportCAL-IPC Profile

 

Senecio angustifolius

OCCNPS Invasive Score:  2.36
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon Report

 

Centaurea diluta SPOTTED KNAPWEED

OCCNPS Invasive Score:  2.50
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon ReportCAL-IPC Profile

 

Parthenium hysterophorus SANTA MARIA FEVERFEW

OCCNPS Invasive Score:  2.57
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon ReportCAL-IPC Profile

 

Dipogon lignosus OKIE BEAN

OCCNPS Invasive Score:  2.64
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon ReportCAL-IPC Profile

 

Euphorbia terracina GERALDTON CARNATION WEED

OCCNPS Invasive Score:  2.64
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon ReportCAL-IPC Profile

 

Centaurea solstitialis YELLOW STARTHISTLE

OCCNPS Invasive Score:  2.71
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon ReportCAL-IPC Profile

 

Rubus armeniacus HIMALAYAN BLACKBERRY

OCCNPS Invasive Score:  2.71
OC Detections and Map:  Calflora Observation Search
Additional Resources:      Calflora Taxon ReportCAL-IPC Profile