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logo Calflora  Illustrated Plant List 

A list of priority invasive species that are NOT yet reliably recorded within Orange County, but expected to be threats. Information at invasives@occnps.org.
33 PLANTS
Perilla frutescens    Small Tree-Mallow


Alternanthera philoxeroides    Alligator weed,  Alligatorweed
invasive non-native
Perennial herb

AMARANTHACEAE

Alternanthera philoxeroides
© 2019 Robin Carter
Alternanthera philoxeroides
© 2023 Ron Vanderhoff
Alternanthera philoxeroides
© 2024 Mike Russler

Ammophila arenaria    Beachgrass,  European beach grass,  European beachgrass
invasive non-native
Perennial grass

POACEAE

Ammophila arenaria
© 2016 Steve Matson
Ammophila arenaria
© 2016 Steve Matson
Ammophila arenaria
© 2016 Steve Matson

Arctotheca calendula    Cape weed
invasive non-native
Annual, Perennial herb

ASTERACEAE

Arctotheca calendula
© 2021 Patrick Hoffman
Arctotheca calendula
© 2023 Nancy Poss
Arctotheca calendula
© 2016 Andrea Pickart

Brassica juncea    Brown mustard,  India mustard
non-native
Annual herb

BRASSICACEAE

Brassica juncea
© 2022 Vernon Smith
Brassica juncea
© 2020 Zoya Akulova
Brassica juncea
© 2021 Zoya Akulova

Carduus tenuiflorus    Italian thistle,  Slender flowered thistle,  Winged plumeless thistle
invasive non-native
Annual herb

ASTERACEAE

Carduus tenuiflorus
© 2018 Gary McDonald
Carduus tenuiflorus
© 2018 Gary McDonald
Carduus tenuiflorus
© 2023 Cynthia Powell

Carrichtera annua    Wards weed
invasive non-native
Annual herb

BRASSICACEAE

Carrichtera annua
© 2023 Ron Vanderhoff
Carrichtera annua
© 2023 Ron Vanderhoff
Carrichtera annua
© 2023 Ron Vanderhoff

Centaurea calcitrapa    Purple star thistle,  Red star thistle
invasive non-native
Annual, Perennial herb

ASTERACEAE

Centaurea calcitrapa
© 2021 R.A. Chasey
Centaurea calcitrapa
© 2019 MCOSD EDRR
Centaurea calcitrapa
© 2022 R.A. Chasey

Centaurea iberica    Iberian knapweed
invasive non-native
Perennial herb

ASTERACEAE

Centaurea iberica
© 2016 Don Thomas
Centaurea iberica
© 2001 CDFA
Centaurea iberica
© 2001 CDFA

Centaurea stoebe    Spotted knapweed
non-native
Perennial herb

ASTERACEAE

Centaurea stoebe
© 2020 Bob Sweatt
Centaurea stoebe
© 2022 BOB CASE
Centaurea stoebe
© 2019 Amanda Mills

Chloris truncata    Australian fingergrass,  Truncate finger grass
non-native
Perennial grass

POACEAE

Chloris truncata
© 2001 CDFA
Chloris truncata
© 2001 CDFA

Chondrilla juncea    Hogbite,  Skeleton weed
invasive non-native
Perennial herb

ASTERACEAE

Chondrilla juncea
© 2021 George Williams
Chondrilla juncea
© 2024 Mike Russler
Chondrilla juncea
© 2021 Bob Sweatt

Cirsium arvense    Canada thistle
invasive non-native
Perennial herb

ASTERACEAE

Cirsium arvense
© 2012 Michael Mitchell
Cirsium arvense
© 2012 Michael Mitchell
Cirsium arvense
© 2022 Donald Burk

Cortaderia jubata    Pampas grass,  Purple pampas grass,  Pampasgrass
invasive non-native
Perennial grass

POACEAE

Cortaderia jubata
© 2018 Ramona Robison
Cortaderia jubata
© 2021 Michelle Karle
Cortaderia jubata
© 2022 Michelle Karle

Cytisus scoparius    Scotch broom,  Scotchbroom
invasive non-native
Shrub

FABACEAE

Cytisus scoparius
© 2016 Steve Matson
Cytisus scoparius
© 2016 Steve Matson
Cytisus scoparius
© 2016 Steve Matson

Dipsacus fullonum    Fuller's teasel,  Fullers' teasel,  Wild teasel
invasive non-native
Perennial herb

DIPSACACEAE

Dipsacus fullonum
© 2022 Morgan Stickrod
Dipsacus fullonum
© 2018 Alex Spencer
Dipsacus fullonum
© 2021 Amber Bedgood

Dipsacus sativus    Fuller's teasel,  Indian teasel
invasive non-native
Annual, Biennial herb

DIPSACACEAE

Dipsacus sativus
© 2019 Danielle Carney
Dipsacus sativus
© 2022 Jennifer Mo
Dipsacus sativus
© 2022 David Strauch

Elaeagnus angustifolia    Oleaster,  Russian olive
invasive non-native
Tree, Shrub

ELAEAGNACEAE

Elaeagnus angustifolia
© 2012 Tim Gibson
Elaeagnus angustifolia
© 2019 Joe Woods
Elaeagnus angustifolia
© 2022 Joe Woods

Elymus caput-medusae    Medusa head
invasive non-native
Annual grass

POACEAE

Elymus caput-medusae
© 2023 Ron Vanderhoff
Elymus caput-medusae
© 2019 Jennifer Mo
Elymus caput-medusae
© 2011 Steve Matson

Enchylaena tomentosa    Ruby saltbush
non-native
Perennial herb

CHENOPODIACEAE

Enchylaena tomentosa
© 2015 Dean Kelch
Enchylaena tomentosa
© 2014 Amy Huie
Enchylaena tomentosa
© 2015 Dean Kelch

Euphorbia dendroides    Tree spurge
non-native
Shrub

EUPHORBIACEAE

Euphorbia dendroides
© 2015 Dean Kelch
Euphorbia dendroides
© 2019 Rachelle Gray
Euphorbia dendroides
© 2023 Keir Morse

Euphorbia virgata    Leafy spurge
invasive non-native
Perennial herb

EUPHORBIACEAE

Euphorbia virgata
© 2023 Nikki Valentine
Euphorbia virgata
© 2019 Lenihan Mazur
Euphorbia virgata
© 2019 Lenihan Mazur

Helichrysum petiolare    Licorice plant
invasive non-native
Shrub, Vine

ASTERACEAE

Helichrysum petiolare
© 2021 Elliot Gunnison
Helichrysum petiolare
© 2022 Mike Russler
Helichrysum petiolare
© 2022 Mike Russler

Heliotropium supinum    Dwarf heliotrope
non-native
Annual herb

HELIOTROPIACEAE


Hydrilla verticillata    Hydrilla,  Waterthyme
invasive non-native
Perennial herb

HYDROCHARITACEAE

Hydrilla verticillata
© 2024 Ron Vanderhoff
Hydrilla verticillata
© 2024 Ron Vanderhoff
Hydrilla verticillata
© 2024 Ron Vanderhoff

Kochia scoparia    Common red sage,  Mexican fireweed,  Summer cypress
invasive non-native
Annual herb

CHENOPODIACEAE

Kochia scoparia
© 2013 Daniel Lubin
Kochia scoparia
© 2023 R.A. Chasey
Kochia scoparia
© 2013 Daniel Lubin

Lepidium appelianum    Hairy whitetop
invasive non-native
Perennial herb

BRASSICACEAE

Lepidium appelianum
© 2023 matsonburger
Lepidium appelianum
© 2023 matsonburger
Lepidium appelianum
© 2019 Richard Spjut

Ludwigia hexapetala    Ludwigia,  Six petal water primrose
invasive non-native
Perennial herb

ONAGRACEAE

Ludwigia hexapetala
© 2009 Keith Gagomiros
Ludwigia hexapetala
© 2021 Charles Russell
Ludwigia hexapetala
© 2019 Ron Vanderhoff

Lythrum salicaria    Purple loosestrife
invasive non-native
Perennial herb

LYTHRACEAE

Lythrum salicaria
© 2023 Donald Burk
Lythrum salicaria
© 2022 Eric Jennings
Lythrum salicaria
© 2020 Katie Rian

Myoporum acuminatum    Strichnine bush
non-native
Tree, Shrub

SCROPHULARIACEAE

Myoporum acuminatum
© 2023 Ron Vanderhoff
Myoporum acuminatum
© 2023 Ron Vanderhoff
Myoporum acuminatum
© 2023 Ron Vanderhoff

Myriophyllum aquaticum    Parrot feather watermilfoil,  Parrot's feather,  Parrotfeather
invasive non-native
Perennial herb (aquatic)

HALORAGACEAE

Myriophyllum aquaticum
© 2019 Patrick Furtado
Myriophyllum aquaticum
© 2016 Ross Hinderer
Myriophyllum aquaticum
© 2019 David popp

Pentameris airoides ssp. airoides    False Hair-grass
non-native
Perennial grass

POACEAE

Pentameris airoides ssp. airoides
© 2016 Keir Morse
Pentameris airoides ssp. airoides
© 2016 Keir Morse
Pentameris airoides ssp. airoides
© 2016 Keir Morse

Ulex europaeus    Common gorse
invasive non-native
Shrub

FABACEAE

Ulex europaeus
© 2025 Cynthia Powell
Ulex europaeus
© 2025 Cynthia Powell
Ulex europaeus
© 2025 Cynthia Powell