Calflora Illustrated Plant List
Northwest region priority species

A combination of eradication & surveillance target species lists for the Northwest region (Humboldt and Del Norte counties).
31 PLANTS
Agrostis avenacea    Pacific bentgrass
invasive non-native
limited

Perennial grass

POACEAE

Agrostis avenacea
© 2025 Ron Vanderhoff
Agrostis avenacea
© 2025 Ron Vanderhoff
Agrostis avenacea
© 2022 Donald Burk
Calflora

CalPhotos

Calscape
Alternanthera philoxeroides    Alligator weed,  Alligatorweed
invasive non-native
high

Perennial herb

AMARANTHACEAE

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

CalPhotos

Calscape
Alyssum murale    yellowtuft
invasive non-native
watch (high risk)

Annual herb

BRASSICACEAE

Alyssum murale
© 2008 Carri Pirosko
Alyssum murale
© 2011 Carri Pirosko
Alyssum murale
© 2008 Carri Pirosko
Calflora

CalPhotos

Calscape
Arundo donax    Giant reed
invasive non-native
high

Perennial grass

POACEAE

Arundo donax
© 2013 Miriam Sachs Martin
Arundo donax
© 2023 Ron Vanderhoff
Arundo donax
© 2021 Ron Vanderhoff
Calflora

CalPhotos

Calscape
Brachypodium distachyon    False brome,  Purple false brome
invasive non-native
moderate

Annual, Perennial grass

POACEAE

Brachypodium distachyon
© 2019 Ron Vanderhoff
Brachypodium distachyon
© 2021 John Rawlings
Brachypodium distachyon
© 2019 Ron Vanderhoff
Calflora

CalPhotos

Calscape
Carduus nutans    Musk thistle,  Nodding plumeless thistle
invasive non-native
moderate

Perennial herb

ASTERACEAE

Carduus nutans
© 2022 Bob Sweatt
Carduus nutans
© 2022 Bob Sweatt
Carduus nutans
© 2022 Bob Sweatt
Calflora

CalPhotos

Calscape
Carthamus lanatus    Woolly distaff thistle
invasive non-native
high

Annual herb

ASTERACEAE

Carthamus lanatus
© 2019 Lenihan Mazur
Carthamus lanatus
© 2019 Danielle Carney
Carthamus lanatus
© 2019 Danielle Carney
Calflora

CalPhotos

Calscape
Centaurea calcitrapa    Purple starthistle,  Purple star thistle,  Red star thistle
invasive non-native
moderate

Annual, Perennial herb

ASTERACEAE

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

CalPhotos

Calscape
Centaurea virgata ssp. squarrosa    Squarrose knapweed
non-native

Perennial herb

ASTERACEAE

Centaurea virgata ssp. squarrosa
© 2013 Gerald Carr
Centaurea virgata ssp. squarrosa
© 2013 Gerald Carr
Centaurea virgata ssp. squarrosa
© 2013 Gerald Carr
Calflora

CalPhotos

Calscape
Chondrilla juncea    Hogbite,  Skeleton weed
invasive non-native
moderate

Perennial herb

ASTERACEAE

Chondrilla juncea
© 2021 George Williams
Chondrilla juncea
© 2024 Mike Russler
Chondrilla juncea
© 2015 John L. Thompson
Calflora

CalPhotos

Calscape
Cynara cardunculus    Artichoke thistle,  Cardoon
invasive non-native
moderate

Perennial herb

ASTERACEAE

Cynara cardunculus
© 2021 R.A. Chasey
Cynara cardunculus
© 2024 Alys Arenas
Cynara cardunculus
© 2022 Allison Rofe
Calflora

CalPhotos

Calscape
Cynoglossum officinale    Gypsyflower,  Hound's tongue,  Purple houndstongue
invasive non-native
moderate

Perennial herb

BORAGINACEAE

Cynoglossum officinale
© 2019 Raymond Gill
Cynoglossum officinale
© 2019 Raymond Gill
Cynoglossum officinale
© 2019 Raymond Gill
Calflora

CalPhotos

Calscape
Dittrichia graveolens    Stinkwort
invasive non-native
moderate

Annual herb

ASTERACEAE

Dittrichia graveolens
© 2017 Bob Huttar
Dittrichia graveolens
© 2019 Ron Vanderhoff
Dittrichia graveolens
© 2019 Ron Vanderhoff
Calflora

CalPhotos

Calscape
Echium pininana    Pine echium
non-native

Shrub

BORAGINACEAE

Echium pininana
© 2014 Alex Beakes
Echium pininana
© 2014 Toni Corelli
Echium pininana
© 2014 Ben Pittenger
Calflora

CalPhotos

Calscape
Eichhornia crassipes    Common water hyacinth
invasive non-native
high

Perennial herb

PONTEDERIACEAE

Eichhornia crassipes
© 2021 Mike Russler
Eichhornia crassipes
© 2015 Judy and Barry Breckling
Eichhornia crassipes
© 2023 Cynthia Powell
Calflora

CalPhotos

Calscape
Euphorbia oblongata    Eggleaf spurge,  Oblong spurge
invasive non-native
limited

Perennial herb

EUPHORBIACEAE

Euphorbia oblongata
© 2017 Gary McDonald
Euphorbia oblongata
© 2019 Randy Huey
Euphorbia oblongata
© 2019 Michael Sturtevant
Calflora

CalPhotos

Calscape
Euphorbia virgata    Leafy spurge
invasive non-native
high

Perennial herb

EUPHORBIACEAE

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

CalPhotos

Calscape
Fallopia japonica    Japanese knotweed
invasive non-native
moderate

Perennial herb

POLYGONACEAE

Fallopia japonica
© 2021 Margot Cunningham
Fallopia japonica
© 2024 Jacob Martin
Fallopia japonica
© 2019 John Malpas
Calflora

CalPhotos

Calscape
Fallopia sachalinensis    Giant knotweed
invasive non-native
moderate

Perennial herb

POLYGONACEAE

Fallopia sachalinensis
© 2024 Patrick Hoffman
Fallopia sachalinensis
© 2024 Patrick Hoffman
Fallopia sachalinensis
© 2023 John Malpas
Calflora

CalPhotos

Calscape
Geranium lucidum    Shiny geranium,  Shining geranium
invasive non-native
watch (high risk)

Annual, Biennial herb

GERANIACEAE

Geranium lucidum
© 2024 Patrick Hoffman
Geranium lucidum
© 2021 Susan Fawcett
Geranium lucidum
© 2025 Mary Ann Machi
Calflora

CalPhotos

Calscape
Hydrilla verticillata    Hydrilla,  Waterthyme
invasive non-native
high

Perennial herb

HYDROCHARITACEAE

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

CalPhotos

Calscape
Kochia scoparia    Common red sage,  Mexican fireweed,  Summer cypress
invasive non-native
limited

Annual herb

CHENOPODIACEAE

Kochia scoparia
© 2025 Ron Vanderhoff
Kochia scoparia
© 2023 R.A. Chasey
Kochia scoparia
© 2025 Ron Vanderhoff
Calflora

CalPhotos

Calscape
Lepidium appelianum    Hairy whitetop
non-native

Perennial herb

BRASSICACEAE

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

CalPhotos

Calscape
Lythrum salicaria    Purple loosestrife
invasive non-native
high

Perennial herb

LYTHRACEAE

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

CalPhotos

Calscape
Onopordum acanthium    Scotch cottonthistle
invasive non-native
high

Perennial herb

ASTERACEAE

Onopordum acanthium
© 2021 Diana Wing
Onopordum acanthium
© 2019 Catherine Talbot
Onopordum acanthium
© 2018 Joe Woods
Calflora

CalPhotos

Calscape
Persicaria wallichii    Himalayan knotweed
invasive non-native
watch (high risk)

Perennial herb

POLYGONACEAE

Persicaria wallichii
© 2017 Redwood Community Action Agency
Persicaria wallichii
© 2019 David Juliano
Persicaria wallichii
© 2014 Ramona Robison
Calflora

CalPhotos

Calscape
Acroptilon repens    Russian knapweed
invasive non-native
moderate

Perennial herb

ASTERACEAE

Acroptilon repens
© 2017 Barbara Boethling
Acroptilon repens
© 2014 Steve Matson
Acroptilon repens
© 2017 Barbara Boethling
Calflora

CalPhotos

Calscape
Sesbania punicea    Red sesbania,  Rattlebox
invasive non-native
high

Shrub

FABACEAE

Sesbania punicea
© 2020 Jennifer Mo
Sesbania punicea
© 2017 Ellen Uhler
Sesbania punicea
© 2025 Mike Russler
Calflora

CalPhotos

Calscape
Tamarix parviflora    Fourstamen tamarisk,  Smallflower tamarisk
invasive non-native
high

Tree, Shrub

TAMARICACEAE

Tamarix parviflora
© 2015 Steve Matson
Tamarix parviflora
© 2020 Leslie Cobb
Tamarix parviflora
© 2015 Steve Matson
Calflora

CalPhotos

Calscape
Tamarix ramosissima    Saltcedar,  Tamarisk
invasive non-native
high

Tree, Shrub

TAMARICACEAE

Tamarix ramosissima
© 2017 Barbara Boethling
Tamarix ramosissima
© 2022 Ron Vanderhoff
Tamarix ramosissima
© 2021 Ron Vanderhoff
Calflora

CalPhotos

Calscape
Watsonia meriana    Bulbil bugle lily
invasive non-native
limited

Perennial herb

IRIDACEAE

Watsonia meriana
© 2017 Juan de Dios Villarino
Watsonia meriana
© 2019 Cynthia Powell
Watsonia meriana
© 2012 John Sayers
Calflora

CalPhotos

Calscape