The Cal-IPC Inventory

The Inventory categorizes plants that threaten California's natural areas. The Inventory includes plants that currently cause damage in California (invasive plants) as well as "Watch" plants that are a high risk of becoming invasive in the future. For information about the Inventory, see "Inventory Details" below.

The Inventory represents the best available knowledge of invasive plant experts in California. Categorization is based on an assessment of ecological impacts, conducted with transparent science-based criteria and expert review. The Inventory has no regulatory authority, and should be used with full understanding of the limitations described here.

Background

Explanation of Cal-IPC ratings

About the Inventory assessment process

History of Inventory Updates (2018-present)

Download the Inventory (CSV)

  • High – These species have severe ecological impacts on physical processes, plant and animal communities, and vegetation structure. Their reproductive biology and other attributes are conducive to moderate to high rates of dispersal and establishment. Most are widely distributed ecologically.
  • Moderate – These species have substantial and apparent-but generally not severe-ecological impacts on physical processes, plant and animal communities, and vegetation structure. Their reproductive biology and other attributes are conducive to moderate to high rates of dispersal, though establishment is generally dependent upon ecological disturbance. Ecological amplitude and distribution may range from limited to widespread.
  • Limited – These species are invasive but their ecological impacts are minor on a statewide level or there was not enough information to justify a higher score. Their reproductive biology and other attributes result in low to moderate rates of invasiveness. Ecological amplitude and distribution are generally limited, but these species may be locally persistent and problematic.
  • Alert – An Alert is listed on species with High or Moderate impacts that have limited distribution in California, but may have the potential to spread much further.
  • Watch – These species have been assessed as posing a high risk of becoming invasive in the future in California.

Assessed, Not on Inventory

Plants are not listed on the Inventory when our assessment finds insignificant current impact and/or insufficient risk of becoming invasive in the future to qualify as a Watch plant. See the list of plants that have been assessed and not added to the Inventory

Pending Assessment

We maintain a list of plants that need to be assessed for current invasiveness or risk of future invasiveness. We draw from this list for periodic updates to the Inventory. See the list of plants pending assessment

Problematic Natives

A handful of native species cause ecological problems where they have been moved outside their historic range in California.
See list of problematic native plants

Using the Inventory table:

  • Click a plant’s Scientific Name to see its Plant Profile page. For the plant’s assessment, click the icon in the far right column, PAF/PRE.
  • The CDFA column lists California Dept. of Food and Agriculture weed ratings (see CDFA definitions here). A checkmark in the Hort column denotes plants that are known from horticulture; the icon in the CWM column links to the CalWeedMapper page for the plant; the icon in the ID card links to a species identification card for the plant, if available (complete listing of Species ID Cards).
  • To sort the table by any column heading (except ID Card), simply click on the column heading. To list only plants from certain Jepson Regions or Habitat Types, use the filters below.
  • “Watch” species are not currently invasive in California. Assessment has found them to be a high risk for becoming invasive in the future.
    • A – A pest of known economic or environmental detriment and is either not known to be established in California or it is present in a limited distribution that allows for the possibility of eradication or successful containment.
    • B – A pest of known economic or environmental detriment and, if present in California, it is of limited distribution.
    • C – A pest of known economic or environmental detriment and, if present in California, it is usually widespread.
    • D – An organism known to be of little or no economic or environmental detriment, to have an extremely low likelihood of weediness, or is known to be a parasite or predator.
    • Q – An organism or disorder suspected to be of economic or environmental detriment, but whose status is uncertain because of incomplete identification or inadequate information.
    • * – An asterisk next to the rating indicates that a plant is included in the CCR Section 4500 list of California State Noxious Weeds.
    • -* – This plant is included in the CCR Section 4500 list of California State Noxious Weeds, but is otherwise not rated.

More details

Use the buttons below to choose plants to display by region, habitat, and whether the plant is designated an invasive plant or a watch plant.

Scientific name Common names Rating Alert CDFA Hort CWM ID card PAF/
PRE
Acacia baileyana cootamundra wattle Watch ✔
Acacia cyclops cyclops Acacia Watch
Acacia dealbata silver wattle Moderate ✔
Acacia longifolia Sydney golden wattle Watch ✔
Acacia melanoxylon blackwood Acacia Limited ✔
Acacia paradoxa kangaroothorn Watch -*
Acacia pycnantha golden wattle Watch
Acacia saligna orange wattle Watch ✔
Acaena novae-zelandiae biddy-biddy Watch -* ✔
Aegilops cylindrica jointed goatgrass Watch -*
Aegilops triuncialis barb goatgrass, barbed goatgrass High -*
Ageratina adenophora eupatory, croftonweed, thoroughwort, sticky snakeroot, catweed, hemp agrimony, sticky agrimony, sticky Eupatorium Moderate B
Agrostis avenacea Pacific bentgrass Limited
Agrostis stolonifera creeping bent; carpet bent; redtop bent; seaside bentgrass Limited ✔
Ailanthus altissima tree-of-heaven; Chinese sumac; paradise-tree; copal-tree Moderate C* ✔
Alhagi maurorum camelthorn Moderate -*
Alliaria petiolata garlic mustard, hedge garlic, Jack-by-the-edge Moderate ◆ A*
Alopecurus pratensis meadow foxtail Watch ✔
Alternanthera philoxeroides alligatorweed High A*
Alyssum corsicum yellowtuft Watch
Alyssum murale yellowtuft Watch
Ambrosia trifida giant ragweed Watch B*
Ammophila arenaria European beachgrass High
Anthoxanthum odoratum sweet vernal grass; vanilla grass Limited
Araujia sericifera bladderflower Watch -* ✔
Arctotheca calendula fertile capeweed Moderate ◆ A* ✔
Arctotheca prostrata capeweed; South African capeweed; cape dandelion; cape gold Moderate ✔
Arum italicum Italian Arum, Italian lords and ladies, large cuckoo pint, orange candleflower Watch ✔
Arundo donax giant reed High -* ✔
Asparagus setaceus common Asparagus fern Watch ✔
Asparagus aethiopicus Asparagus fern, Sprenger's Asparagus, foxtail fern Watch ✔
Asparagus asparagoides bridal creeper; African Asparagus fern; ornamental Asparagus; smilax Asparagus Moderate ◆ ✔
Asphodelus fistulosus onion weed; asphodel; hollow stemmed asphodel; wild onion Moderate ◆ -* ✔
Atriplex semibaccata Australian saltbush; berry saltbush; creeping saltbush; scrambing berry saltbush Moderate ✔
Avena barbata slender oat Moderate
Avena fatua wild oats Moderate
Bassia hyssopifolia five-hook Bassia; five horn Bassia; five-horn smotherweed; hyssop-leaved echinopsilon; smotherweed; thorn orache; Limited
Bellardia trixago Bellardia; mediterranean lineseed Limited
Berberis darwinii Darwin barberry Watch ✔
Berteroa incana hoary Alyssum Watch -*
Brachypodium distachyon annual false-brome; false brome; purple false brome; stiff brome Moderate
Brachypodium sylvaticum slender false-brome; false-brome Moderate ◆ -*
Brassica nigra black mustard Moderate
Brassica rapa field mustard; turnip Limited
Brassica tournefortii Sahara mustard; Morrocan mustard; Asian mustard High C
Briza maxima big quakinggrass; rattlesnake grass; large quakinggrass, Limited ✔
Bromus diandrus ripgut brome; great brome; ripgut grass Moderate
Bromus hordeaceus soft brome; soft chess; lopgrass Limited
Bromus japonicus Japanese brome; Japanese chess Limited
Bromus madritensis ssp. rubens red brome; foxtail chess High
Bromus tectorum cheatgrass; downy brome High C
Buddleja davidii butterfly bush Watch ✔
Cakile maritima European sea rocket Limited
Lepidium chalepense lens-podded hoary cress; lens-podded whitetop; hoary cress; peppergrass; whitetop; whiteweed; cranson rampant; chalapa whitetop
Lepidium draba heart-podded hoary cress, whitetop
Lepidium appelianum hairy whitetop
Carduus acanthoides plumeless thistle; bristly thistle; giant plumeless thistle; spiny thistle Limited -*
Carduus nutans musk thistle; giant plumeless thistle; nodding (plumeless) thistle; Moderate -*
Carduus pycnocephalus Italian thistle Moderate C*
Carduus tenuiflorus slenderflower thistle; Italian thistle; multiheaded thistle; seaside thistle; shore thistle; winged plumeless thistle Limited -*
Carex pendula hanging sedge Watch ✔
Carpobrotus chilensis sea fig; iceplant Moderate ✔
Carpobrotus edulis highway iceplant High ✔
Carrichtera annua Ward's weed Moderate ◆ A
Carthamus lanatus woolly distaff thistle; false starthistle; saffron thistle; woolly safflower; woolly starthistle High -*
Casuarina equisetifolia beach sheoak Watch ✔
Catharanthus roseus Madagascar periwinkle Watch ✔
Cenchrus echinatus southern sandbur Watch B*
Cenchrus longispinus mat sandbur Watch B*
Centaurea calcitrapa purple starthistle Moderate -*
Centaurea jacea ssp. pratensis meadow knapweed
Centaurea diffusa diffuse knapweed Moderate -*
Centaurea diluta North African knapweed Watch
Centaurea jacea ssp. pratensis meadow knapweed Moderate ◆ -*
Centaurea melitensis tocalote; Malta starthistle Moderate -*
Centaurea solstitialis yellow starthistle High -*
Centaurea stoebe ssp. micranthos spotted knapweed High -*
Centaurea virgata var. squarrosa squarrose knapweed Moderate -*
Cestrum parqui willow jessamine Watch ✔
Chasmanthe floribunda African cornflag Watch ✔
Chondrilla juncea skeleton weed; devil's grass; hogbite; gum succory; naked weed Moderate -*
Chrysanthemoides monilifera ssp. monilifera boneseed; Higgin's curse; jungle flower; Moderate ◆ A
Glebionis coronaria garland Chrysanthemum; crown daisy
Cirsium arvense Canada thistle Moderate -*
Cirsium vulgare bull thistle Moderate -*
Clematis vitalba old man's beard; traveler's joy Moderate ◆ A ✔
Colocasia esculenta taro root; wild taro; coco-yam; eddo; elephant-ear-plant Moderate ◆
Conicosia pugioniformis narrowleaf iceplant; false iceplant; conicosia Limited
Conium maculatum poison-hemlock Moderate
Cordyline australis New Zealand cabbage tree; cabbage tree; Ti Kouka; giant dracaena [dracena]; dracaena palm
Cortaderia jubata jubatagrass; pink pampasgrass High -* ✔
Cortaderia selloana pampasgrass; white pampasgrass High ✔
Cotoneaster franchetii orange Cotoneaster; Cotoneaster; Francheti Cotoneaster Moderate ✔
Cotoneaster lacteus milkflower Cotoneaster; Parney's Cotoneaster Moderate ✔
Cotoneaster pannosus silverleaf Cotoneaster; velvet Cotoneaster Moderate ✔
Cotula coronopifolia common brassbuttons Limited ✔
Crataegus monogyna English hawthorn; common hawthorn; oneseed hawthorn; May tree; singleseed hawthorn; azzarola; neapolitan medlar; oneseed hawthorn; whitethorn; Limited ✔
Crocosmia x crocosmiiflora montbretia Limited ✔
Crupina vulgaris common Crupina Limited A*
Cuscuta japonica Japanese dodder Watch -*
Cynara cardunculus artichoke thistle; cardoon; wild artichoke Moderate -* ✔
Cynodon dactylon Bermuda grass; couch grass; devil grass; wire grass; vine grass; bermudagrass Moderate ✔
Cynoglossum officinale common houndstongue; beggar's-lice; dog bur; dog's tongue; glovewort; gypsyflower; sheelice; sticktight; woolmat Moderate ✔
Cynosurus echinatus hedgehog dogtail; annual dogtail; bristly dogtail grass; hedgehoggy Moderate
Cytisus multiflorus white Spanish broom Watch
Cytisus proliferus tagasaste Watch
Cytisus scoparius Scotch broom; English broom; common broom High -* ✔
Cytisus striatus Portuguese broom; hairy-fruited broom Moderate B ✔
Dactylis glomerata orchard grass Limited ✔
Datura inoxia pricklyburr Watch ✔
Delairea odorata Cape-ivy; German ivy; Italian ivy; ivy groundsel; parlor ivy; water ivy High -* ✔
Descurainia sophia tansy mustard, flixweed Limited
Digitalis purpurea foxglove Limited ✔
Dipogon lignosus Cape sweet pea, okie bean Watch ✔
Dipsacus fullonum wild teasel; common teasel; card thistle; Fuller's teasel Moderate ✔
Dipsacus laciniatus cutleaf teasel Watch
Dipsacus sativus Fuller's teasel Moderate
Dittrichia graveolens stinkwort; stinkweed; Khaki weed; Moderate ◆ -*
Dittrichia viscosa false yellowhead Watch A
Echium candicans pride-of-Madeira Limited ✔
Echium plantagineum Patterson's curse Watch A
Egeria densa Brazilian Egeria; Egeria High ✔
Ehrharta calycina purple veldtgrass; African veldtgrass; perennial veldt grass High
Ehrharta erecta panic veldtgrass; Ehrharta; Lamarck's Ehrharta; panic veld grass; Stebbin's grass Moderate
Ehrharta longiflora long-flowered veldtgrass Limited
Eichhornia crassipes water hyacinth High ✔
Elaeagnus angustifolia Russian olive; oleaster Moderate ✔
Elymus caput-medusae medusahead High -*
Emex spinosa devil's thorn; spiny threecornerjack Moderate ◆
Senecio glomeratus cutleaf burnweed; cutleaf fireweed; New Zealand fireweed; Australian burnweed; bushman's burnweed; cut-leaved coast fireweed; Australian fireweed; little fireweed; coastal burnweed; Australian burnweed; toothed coast fireweed
Erica lusitanica Spanish heath; Portuguese heath; urze Limited B ✔
Erodium cicutarium redstem filaree; redstem stork's bill; filaree Limited ✔
Eucalyptus camaldulensis red gum; river red gum; Red River gum Limited ✔
Eucalyptus cladocalyx sugargum Watch ✔
Eucalyptus globulus blue gum; Tasmanian blue gum; blue gum Eucalyptus; common Eucalyptus; Southern blue gum; Victorian blue gum Limited ✔
Euphorbia lathyris caper spurge Watch ✔
Euphorbia myrsinites myrtle spurge, creeping spurge Watch A ✔
Euphorbia oblongata eggleaf spurge; oblong spurge Limited -* ✔
Euphorbia terracina carnation spurge; Geraldton carnationweed Limited -*
Euphorbia virgata leafy spurge; faitours-grass; wolf's milk High -*
Fallopia ×bohemica Bohemian knotweed Watch A ✔
Fallopia japonica Japanese knotweed; Mexican bamboo Moderate ◆ A*
Fallopia sachalinensis giant knotweed; sakhalin knotweed; sacaline Moderate ◆ A*
Festuca arundinacea reed fescue; alta fescue; coarse fescue; rescue; reed fescue; tall fescue; Kentucky fescue Moderate ✔
Festuca myuros rat-tail fescue; red-tailed fescue; sixweeksgrass; zorro annual fescue Moderate
Festuca perennis Italian ryegrass Moderate
Ficus carica edible fig Moderate ✔
Foeniculum vulgare fennel; sweet fennel; sweet anise Moderate ✔
Galega officinalis professorweed Watch A*
Galenia pubescens coastal Galenia, Galenia, blanket weed, carpet weed, green Galenia Watch
Gazania linearis Gazania; treasure flower Moderate ◆ ✔
Genista linifolia Mediterranean broom Watch
Genista monosperma bridal veil broom Moderate ◆ -*
Genista linifolia
Genista monspessulana French broom; soft broom; canary broom; Montepellier broom High C* ✔
Geranium dissectum cutleaf Geranium Limited
Geranium lucidum shining Geranium Watch A ✔
Geranium purpureum little robin Limited
Glebionis coronaria garland Chrysanthemum, crown daisy Limited
Glyceria declinata mannagrass; sweetgrass; waxy mannagrass Moderate
Grevillea robusta silkoak Watch ✔
Gunnera tinctoria Chilean Gunnera Watch ✔
Gypsophila paniculata baby's breath Watch B ✔
Halogeton glomeratus Halogeton Moderate B*
Hedera canariensis Algerian ivy High ✔
Hedera helix English ivy High ✔
Helianthus tuberosus Jerusalem artichoke Watch ✔
Helichrysum petiolare licorice plant Limited ✔
Helichrysum petiolare
Heliotropium amplexicaule clasping heliotrope Watch
Helminthotheca echioides bristly ox-tongue; bugloss; bugloss-picris Limited
Heracleum mantegazzianum giant hogweed Watch A
Hieracium aurantiacum orange hawkweed Watch B ✔
Hirschfeldia incana short-pod mustard; Mediterranean mustard; summer mustard; Greek mustard Moderate ✔
Holcus lanatus common velvet grass; Yorkshire fog Moderate ✔
Hordeum marinum Mediterranean barley; seaside barley Moderate
Hordeum murinum hare barley, foxtail, wild barley, wall barley, smooth barley Moderate
Hydrilla verticillata Hydrilla; water thyme; Florida Elodea High A*
Hyparrhenia hirta Tambookie grass Watch
Hypericum androsaemum sweet-amber Watch ✔
Hypericum canariense Canary Island St. Johnswort; Grenadillo Moderate ◆ B* ✔
Hypericum grandifolium large-leaved Hypericum Watch
Hypericum perforatum St. John's wort; klamathweed; tipton weed; goatweed Limited C* ✔
Hypochaeris glabra smooth cat's-ear Limited
Hypochaeris radicata rough cat's-ear; false dandelion Moderate
Ilex aquifolium English holly Limited ✔
Impatiens glandulifera Himalayan balsam, ornamental jewelweed, Indian balsam, policeman's-helmet Watch ✔
Ipomoea indica blue morning glory Watch ✔
Iris pseudacorus yellowflag Iris; pale yellow Iris Limited B ✔
Isatis tinctoria dyer's woad Moderate -* ✔
Kniphofia uvaria redhot poker Watch ✔
Kochia scoparia Kochia; belvedere; belvedere-cypress; fireball; fireweed; Mexican burningbush; mock cypress Limited ✔
Lantana camara Lantana Watch ✔
Lathyrus latifolius perennial sweet pea, sweet pea, everlasting pea Watch ✔
Lepidium appelianum hairy whitetop
Lepidium chalepense lens-podded hoary cress, lens-podded whitetop, hoary cress, peppergrass; whitetop, whiteweed, cranson rampant, chalapa whitetop Moderate ◆ -*
Lepidium draba heart-podded hoary cress, whitetop Moderate -*
Lepidium latifolium perennial pepperweed; tall whitetop; broadleaved pepperweed High -*
Leptospermum laevigatum Australian tea tree Watch ✔
Leucanthemum vulgare ox-eye daisy; dog daisy; margriet; marguerite daisy; moon daisy; white daisy; yellow daisy; Moderate ✔
Ligustrum lucidum glossy privet; broad-leaved privet; tree privet Limited
Limnobium spongia South American spongeplant; West Indian spongeplant High -*
Limonium duriusculum European sea lavender Moderate B
Limonium ramosissimum Algerian sea lavender Limited B
Linaria dalmatica ssp. dalmatica Dalmatian toadflax, broad-leaved toadflax, wild snapdragon Moderate -*
Linaria dalmatica ssp. dalmatica Dalmatian toadflax; broad-leaved toadflax; wild snapdragon
Linaria vulgaris yellow toadflax; butter and eggs; common linaria; common toadflax; wild snapdragon Moderate ✔
Lobularia maritima sweet Alyssum; sweet alison; seaside Alyssum; seaside Lobularia Limited ✔
Ludwigia hexapetala creeping waterprimrose; Uruguay waterprimrose High C* ✔
Ludwigia peploides floating water primrose; California waterprimrose High ✔
Lupinus arboreus
Lythrum hyssopifolia hyssop loosestrife; grass poly; hyssop lythrum Moderate
Lythrum junceum creeping loosestrife, rose loosestrife Watch ✔
Lythrum salicaria purple loosestrife High -* ✔
Malephora crocea coppery Mesembryanthemum Watch ✔
Marrubium vulgare horehound; white horehound Limited ✔
Maytenus boaria mayten Watch ✔
Medicago polymorpha California burclover; burr medic Limited
Melia azedarach Chinaberry tree, Pride of India, bead-tree, Cape-lilac, syringaberry tree, Persian lilac, Indian lilac, white cedar Watch ✔
Melinis repens Natal grass, natalgrass, Natal redtop, rose natal grass, Zizka Watch ✔
Mentha pulegium pennyroyal; European pennyroyal; grows-in-a-ditch Moderate ✔
Mesembryanthemum crystallinum crystalline iceplant; common iceplant Moderate ◆ ✔
Mesembryanthemum nodiflorum slenderleaf iceplant; small flowered iceplant Limited
Myoporum laetum ngaio tree; false sandalwood; mousehole tree Moderate ✔
Myosotis latifolia common forget-me-not; wood forget-me-not; broadleaf forget-me-not Limited ✔
Myriophyllum aquaticum parrotfeather; Brazilian watermilfoil; parrotfeather watermilfoil; thread-of-life; High C ✔
Myriophyllum spicatum spike watermilfoil, Eurasian watermilfoil High
Nardus stricta matgrass Watch
Nassella trichotoma serrated tussock, serrated tussock grass, Yass tussock, Yass River tussock Watch ✔
Nassella manicata
Nicotiana glauca tree tobacco Moderate ✔
Nothoscordum gracile false garlic Watch -*
Olea europaea olive Limited ✔
Oncosiphon pilulifer stinknet; globe chamomile High Q
Ononis alopecuroides foxtail restharrow Limited -*
Onopordum acanthium Scotch thistle; cotton thistle; woolly thistle; winged thistle; jackass thistle; heraldic thistle High -* ✔
Onopordum illyricum Illyerian thistle Watch -*
Orobanche aegyptiaca Egyptian broomrape Watch A
Osteospermum calendulaceum Watch A
Oxalis pes-caprae Bermuda buttercup; buttercup oxalis; sour grass Moderate
Paraserianthes lophantha plume Acacia Watch
Parentucellia viscosa yellow glandweed; sticky Parentucellia; broadleaved glandweed Limited
Parthenium hysterophorus Santa Maria feverfew Watch A*
Paspalum urvillei Vasey's grass Watch
Paspalum vaginatum seashore Paspalum Watch ✔
Passiflora tarminiana banana passionfruit Watch
Peganum harmala African-rue Watch -* ✔
Pennisetum ciliare buffelgrass, buffel grass Watch ✔
Pennisetum clandestinum Kikuyu grass Limited C*
Pennisetum setaceum crimson fountain grass; purple fountain grass; tender fountain grass Moderate ✔
Pennisetum villosum feathertop Watch ✔
Persicaria wallichii Himalayan knotweed Watch -* ✔
Phalaris aquatica harding grass; bulbous canarygrass; phalaris; toowoomba grass Moderate ✔
Phoenix canariensis Canary Island date palm Limited ✔
Phragmites australis common reed
Phytolacca americana common pokeweed; American cancer; American pokeweed; cancer jalap; coakum; garget; inkberry; pigeonberry; poke; poke sallet; pokeberry; pokeweed; red-ink plant; redweed; scoke; Virgina poke Limited ✔
Stipa miliacea var. miliacea smilo grass; bamboo grass; milo; ricegrass; rice millet; millet mountain-rice; San Diego grass
Pittosporum undulatum Victorian box Watch ✔
Plantago lanceolata English plantain; buckhorn plantain; buck plantain; black-jacks; narrowleaf plantain; lanceleaf plantain; ribbed plantain; ribgrass; ribwort Limited ✔
Plecostachys serpyllifolia petite-licorice Watch ✔
Poa pratensis Kentucky bluegrass; smooth meadowgrass Limited ✔
Polygala myrtifolia myrtle-leaf milkwort Watch
Polypogon monspeliensis rabbitsfoot grass; annual beardgrass; rabbitfootgrass; tawny beardgrass Limited
Potamogeton crispus curly-leaved pondweed; curled pondweed; curly pondweed Moderate
Potentilla recta sulphur cinquefoil; rough-fruited cinquefoil, erect cinquefoil Watch -* ✔
Prunus cerasifera cherry plum; Myrobalan plum; Pissard plum; purpleleaf plum Limited ✔
Pulicaria paludosa Spanish false fleabane, Spanish sunflower Watch
Pyracantha angustifolia narrowleaf firethorn; slender firethorn; woolly firethorn Limited ✔
Pyracantha coccinea scarlet firethorn, firethorn Limited
Pyracantha crenulata Nepalese firethorn, Himalayan firethorn, Nepal firethorn Limited
Pyrus calleryana Callery pear Watch ✔
Ranunculus repens creeping buttercup Limited ✔
Raphanus sativus wild radish Limited
Rhamnus alaternus Italian buckthorn Watch ✔
Rhaponticum repens Russian knapweed, hardheads, creeping knapweed, mountain bluet, Turkestan thistle Moderate B*
Ricinus communis castor bean Limited ✔
Robinia pseudoacacia black locust Limited ✔
Romulea rosea var. australis rosy sandcrocus Watch
Rubus armeniacus Himalayan blackberry High ✔
Rumex acetosella sheep sorrel Moderate ✔
Rumex crispus curly dock Limited
Rytidosperma caespitosum wallabygrass Watch
Rytidosperma penicillatum hairy wallaby grass; hairy oat grass Limited
Saccharum ravennae ravennagrass; hardy pampas grass; plume grass; canna di Ravenna Moderate ◆ B* ✔
Salpichroa origanifolia lily of the valley vine Watch C
Salsola paulsenii barbwire Russian thistle Limited -*
Salsola ryanii Ryan's Russian thistle Watch
Salsola soda glasswort; oppositeleaf Russian thistle Moderate
Salsola tragus Russian thistle; common saltwort; prickly Russian thistle; Russian tumbleweed; tumbleweed; tumbling weed; windwitch; witchweed; prickly glasswort Limited C*
Salvia aethiopis Mediterranean sage; African sage Limited -* ✔
Salvinia molesta giant Salvinia; karibaweed; water velvet; African pyle; aquarium watermoss; water fern; koi kandy High -*
Saponaria officinalis bouncing-bet; bouncing betty; soapwort; goodbye summer Limited ✔
Scabiosa atropurpurea pincushion flower Watch ✔
Schinus molle Peruvian peppertree; California peppertree Limited ✔
Schinus terebinthifolia Brazilian pepper tree; Christmas-berry tree; Christmasberry; Florida holly Moderate ◆ ✔
Schismus arabicus Mediterranean grass; Arabian schismus Limited
Schismus barbatus common Mediterranean grass; Old han schismus Limited
Scolymus hispanicus goldenthistle Watch -*
Senecio elegans redpurple ragwort, purple ragwort, wild cineraria Watch ✔
Senecio glomeratus cutleaf burnweed, cutleaf fireweed, New Zealand fireweed, Australian burnweed, bushman's burnweed, cut-leaved coast fireweed, Australian fireweed, little fireweed, coastal burnweed, Australian burnweed, toothed coast fireweed Moderate
Senecio jacobaea tansy ragwort; stinking willie; stavewort; kettle-dock; felonweed; Fairies' horse; tansy butterweed; staggerwort Limited -*
Senecio linearifolius fireweed groundsel Watch -*
Sesbania punicea scarlet Wisteria; red Sesbania; rattlebox; Chinese Wisteria High -* ✔
Silybum marianum milk thistle; variegated thistle; blessed milk thistle; Virgin Mary's thistle; Lady's milk; Holy thistle; spotted thistle; cabbage thistle; spotted thistle; St. Mary's thistle; white thistle Limited ✔
Sinapis arvensis wild mustard; canola; charlock mustard; common mustard; crunch-weed; field kale; field mustard; kedlock; rapeseed Limited
Sisymbrium irio London rocket Limited
Solanum aviculare New Zealand nightshade Watch ✔
Solanum carolinense Carolina horsenettle Watch -*
Spartina alterniflora x S. foliosa smooth hybrid cordgrass High -*
Spartina anglica English cordgrass Moderate ◆ -*
Spartina densiflora dense-flowered cordgrass; Chilean cordgrass. High -*
Spartina patens salt marsh hay Limited -*
Spartium junceum Spanish broom High -* ✔
Sphaerophysa salsula alkali swainsonpea Watch -*
Stipa brachychaeta punagrass Watch -*
Stipa capensis Cape ricegrass, Mediterranean steppegrass, twisted-awned speargrass Moderate ◆
Stipa manicata Andean tussockgrass; tropical needlegrass Limited
Stipa miliacea var. miliacea smilo grass; bamboo grass; milo; ricegrass; rice millet; millet mountain-rice; San Diego grass Limited
Stipa tenuissima Mexican feathergrass Watch ✔
Tamarix aphylla athel; athel pine; tamarisk; evergreen saltcedar Limited B ✔
Tamarix chinensis Chinese tamarisk, fivestamen tamarisk High -*
Tamarix gallica French tamarisk High -*
Tamarix parviflora smallflower tamarisk High -* ✔
Tamarix ramosissima saltcedar; tamarisk High -* ✔
Tanacetum vulgare common tansy; golden buttons; garden tansy Moderate ✔
Tetragonia tetragonioides New Zealand spinach; warrigal greens Limited
Thinopyrum junceiforme Russian wheatgrass Watch
Torilis arvensis hedgeparsley; spreading hedgeparsley Moderate
Triadica sebifera Chinese tallow tree; popcorn tree; chicken tree; Florida aspen; Vegetable tallow; white wax berry Moderate ◆ ✔
Tribulus terrestris puncture vine; puncturevine, goat's head Limited -*
Trifolium hirtum rose clover Limited
Ulex europaeus gorse; common gorse; furze; prickly broom High -*
Undaria pinnatifida wakame; Japanese kelp; Asian seaweed Limited
Ventenata dubia North Africa grass Watch
Verbascum thapsus woolly mullein; common mullein; lungwort; feltwort; torches; Jacob's staff; velvetplant; old man's flannel; miner's candle Limited ✔
Verbena bonariensis tall vervain Watch ✔
Vinca major periwinkle; bigleaf periwinkle; greater periwinkle; blue periwinkle; myrtle Moderate ✔
Volutaria tubuliflora desert knapweed; Mediterranean knapweed Limited ◆ A*
Washingtonia robusta Mexican fan palm; Washington palm; skyduster; thread palm Moderate ◆ ✔
Watsonia meriana bulbil Watsonia; Watsonia Limited ✔
Zantedeschia aethiopica calla lily; arum lily Limited ✔
Zostera japonica dwarf eelgrass; Japanese eelgrass Moderate ◆ -*
Zygophyllum fabago Syrian beancaper Watch -*