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 Report, CAL-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 Report, CAL-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 Report, CAL-IPC Profile
Volutaria tubuliflora – EGYPTIAN KNAPWEED
OCCNPS Invasive Score: 1.86
OC Detections and Map: Calflora Observation Search
Additional Resources: Calflora Taxon Report, CAL-IPC Profile
Chrysanthemoides monilifera ssp. monilifera – BITOU BUSH
OCCNPS Invasive Score: 2.00
OC Detections and Map: Calflora Observation Search
Additional Resources: Calflora Taxon Report, CAL-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 Report, CAL-IPC Profile
Senecio angustifolius
OCCNPS Invasive Score: 2.36
OC Detections and Map: Calflora Observation Search
Additional Resources: Calflora Taxon Report
Centaurea diluta – NORTH AFRICAN KNAPWEED
OCCNPS Invasive Score: 2.50
OC Detections and Map: Calflora Observation Search
Additional Resources: Calflora Taxon Report, CAL-IPC Profile
Parthenium hysterophorus – SANTA MARIA FEVERFEW
OCCNPS Invasive Score: 2.57
OC Detections and Map: Calflora Observation Search
Additional Resources: Calflora Taxon Report, CAL-IPC Profile
Dipogon lignosus – OKIE BEAN
OCCNPS Invasive Score: 2.64
OC Detections and Map: Calflora Observation Search
Additional Resources: Calflora Taxon Report, CAL-IPC Profile
Euphorbia terracina – GERALDTON CARNATION WEED
OCCNPS Invasive Score: 2.64
OC Detections and Map: Calflora Observation Search
Additional Resources: Calflora Taxon Report, CAL-IPC Profile
Centaurea solstitialis – YELLOW STARTHISTLE
OCCNPS Invasive Score: 2.71
OC Detections and Map: Calflora Observation Search
Additional Resources: Calflora Taxon Report, CAL-IPC Profile
Rubus armeniacus – HIMALAYAN BLACKBERRY
OCCNPS Invasive Score: 2.71
OC Detections and Map: Calflora Observation Search
Additional Resources: Calflora Taxon Report, CAL-IPC Profile