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 nameCommon namesRatingAlertCDFAHortCWMID cardPAF/
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 High -*
Ageratina adenophora eupatory Moderate B
Agrostis avenacea Pacific bentgrass Limited
Agrostis stolonifera creeping bent Limited ✔
Ailanthus altissima tree-of-heaven Moderate C* ✔
Alhagi maurorum camelthorn Moderate -*
Alliaria petiolata garlic mustard 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 Limited
Araujia sericifera bladderflower Watch -* ✔
Arctotheca calendula fertile capeweed Moderate◆A* ✔
Arctotheca prostrata capeweed Moderate ✔
Arum italicum Italian Arum Watch ✔
Arundo donax giant reed High -* ✔
Asparagus aethiopicus Asparagus fern Watch ✔
Asparagus asparagoides bridal creeper Moderate◆ ✔
Asphodelus fistulosus onion weed Moderate◆-* ✔
Atriplex semibaccata Australian saltbush Moderate ✔
Avena barbata slender oat Moderate
Avena fatua wild oats Moderate
Bassia hyssopifolia five-hook Bassia Limited
Bellardia trixago Bellardia Limited
Berberis darwinii Darwin barberry Watch ✔
Berteroa incana hoary Alyssum Watch -*
Brachypodium distachyon annual false-brome Moderate
Brachypodium sylvaticum slender false-brome Moderate◆-*
Brassica nigra black mustard Moderate
Brassica rapa field mustard Limited
Brassica tournefortii Sahara mustard High C
Briza maxima big quakinggrass Limited ✔
Bromus diandrus ripgut brome Moderate
Bromus hordeaceus soft brome Limited
Bromus japonicus Japanese brome Limited
Bromus madritensis ssp. rubens red brome High
Bromus tectorum cheatgrass High C
Buddleja davidii butterfly bush Watch ✔
Cakile maritima European sea rocket Limited
Carduus acanthoides plumeless thistle Limited -*
Carduus nutans musk thistle Moderate -*
Carduus pycnocephalus Italian thistle Moderate -*
Carduus tenuiflorus slenderflower thistle Limited -*
Carex pendula hanging sedge Watch ✔
Carpobrotus chilensis sea fig Moderate ✔
Carpobrotus edulis highway iceplant High ✔
Carrichtera annua Ward's weed Moderate◆A
Carthamus lanatus woolly distaff thistle 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 diffusa diffuse knapweed Moderate -*
Centaurea diluta North African knapweed Watch
Centaurea jacea ssp. pratensis meadow knapweed Moderate◆-*
Centaurea melitensis tocalote 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 Moderate -*
Chrysanthemoides monilifera ssp. monilifera boneseed Moderate◆A
Cirsium arvense Canada thistle Moderate -*
Cirsium vulgare bull thistle Moderate -*
Clematis vitalba old man's beard Moderate◆A ✔
Colocasia esculenta taro root Moderate◆
Conicosia pugioniformis narrowleaf iceplant Limited
Conium maculatum poison-hemlock Moderate
Cortaderia jubata jubatagrass High -* ✔
Cortaderia selloana pampasgrass High ✔
Cotoneaster franchetii orange Cotoneaster Moderate ✔
Cotoneaster lacteus milkflower Cotoneaster Moderate ✔
Cotoneaster pannosus silverleaf Cotoneaster Moderate ✔
Cotula coronopifolia common brassbuttons Limited ✔
Crataegus monogyna English hawthorn Limited ✔
Crocosmia x crocosmiiflora montbretia Limited ✔
Crupina vulgaris common Crupina Limited A*
Cynara cardunculus artichoke thistle Moderate -* ✔
Cynodon dactylon Bermuda grass Moderate ✔
Cynoglossum officinale common houndstongue Moderate ✔
Cynosurus echinatus hedgehog dogtail Moderate
Cytisus multiflorus white Spanish broom Watch
Cytisus proliferus tagasaste Watch
Cytisus scoparius Scotch broom High -* ✔
Cytisus striatus Portuguese broom Moderate B ✔
Dactylis glomerata orchard grass Limited ✔
Datura inoxia pricklyburr Watch ✔
Delairea odorata Cape-ivy High -* ✔
Descurainia sophia tansy mustard Limited
Digitalis purpurea foxglove Limited ✔
Dipogon lignosus Cape sweet pea Watch ✔
Dipsacus fullonum wild teasel Moderate ✔
Dipsacus laciniatus cutleaf teasel Watch
Dipsacus sativus Fuller's teasel Moderate
Dittrichia graveolens stinkwort Moderate◆-*
Dittrichia viscosa false yellowhead Watch A
Echium candicans pride-of-Madeira Limited ✔
Echium plantagineum Patterson's curse Watch A
Egeria densa Brazilian Egeria High ✔
Ehrharta calycina purple veldtgrass High
Ehrharta erecta panic veldtgrass Moderate
Ehrharta longiflora long-flowered veldtgrass Limited
Eichhornia crassipes water hyacinth High ✔
Elaeagnus angustifolia Russian olive Moderate ✔
Elymus caput-medusae medusahead High -*
Emex spinosa devil's thorn Moderate◆
Erica lusitanica Spanish heath Limited B ✔
Erodium cicutarium redstem filaree Limited ✔
Eucalyptus camaldulensis red gum Limited ✔
Eucalyptus cladocalyx sugargum Watch ✔
Eucalyptus globulus blue gum Limited ✔
Euphorbia lathyris caper spurge Watch ✔
Euphorbia myrsinites myrtle spurge Watch A ✔
Euphorbia oblongata eggleaf spurge Limited -* ✔
Euphorbia terracina carnation spurge Limited -*
Euphorbia virgata leafy spurge High -*
Fallopia ×bohemica Bohemian knotweed Watch A ✔
Fallopia japonica Japanese knotweed Moderate◆A*
Fallopia sachalinensis giant knotweed Moderate◆A*
Festuca arundinacea reed fescue Moderate ✔
Festuca myuros rat-tail fescue Moderate
Festuca perennis Italian ryegrass Moderate
Ficus carica edible fig Moderate ✔
Foeniculum vulgare fennel Moderate ✔
Galega officinalis professorweed Watch A*
Gazania linearis Gazania Moderate◆ ✔
Genista linifolia Mediterranean broom Watch
Genista monosperma bridal veil broom Moderate◆-*
Genista monspessulana French broom High C* ✔
Geranium dissectum cutleaf Geranium Limited
Geranium lucidum shining Geranium Watch A ✔
Geranium purpureum little robin Limited
Glebionis coronaria garland Chrysanthemum Limited
Glyceria declinata 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 ✔
Heliotropium amplexicaule clasping heliotrope Watch
Helminthotheca echioides bristly ox-tongue Limited
Heracleum mantegazzianum giant hogweed Watch A
Hieracium aurantiacum orange hawkweed Watch B ✔
Hirschfeldia incana short-pod mustard Moderate ✔
Holcus lanatus common velvet grass Moderate ✔
Hordeum marinum Mediterranean barley Moderate
Hordeum murinum hare barley Moderate
Hydrilla verticillata Hydrilla High A*
Hyparrhenia hirta Tambookie grass Watch
Hypericum androsaemum sweet-amber Watch ✔
Hypericum canariense Canary Island St. Johnswort Moderate◆B* ✔
Hypericum grandifolium large-leaved Hypericum Watch
Hypericum perforatum St. John's wort Limited C* ✔
Hypochaeris glabra smooth cat's-ear Limited
Hypochaeris radicata rough cat's-ear Moderate
Ilex aquifolium English holly Limited ✔
Ipomoea indica blue morning glory Watch ✔
Iris pseudacorus yellowflag Iris Limited B ✔
Isatis tinctoria dyer's woad Moderate -* ✔
Kniphofia uvaria redhot poker Watch ✔
Kochia scoparia Kochia Limited ✔
Lantana camara Lantana Watch ✔
Lathyrus latifolius perennial sweet pea Watch ✔
Lepidium chalepense lens-podded hoary cress Moderate◆-*
Lepidium draba heart-podded hoary cress Moderate -*
Lepidium latifolium perennial pepperweed High -*
Leptospermum laevigatum Australian tea tree Watch ✔
Leucanthemum vulgare ox-eye daisy Moderate ✔
Ligustrum lucidum glossy privet Limited
Limnobium spongia South American spongeplant High -*
Limonium duriusculum European sea lavender Moderate B
Limonium ramosissimum Algerian sea lavender Limited B
Linaria dalmatica ssp. dalmatica Dalmatian toadflax Moderate -*
Linaria vulgaris yellow toadflax Moderate ✔
Lobularia maritima sweet Alyssum Limited ✔
Ludwigia hexapetala creeping waterprimrose High C* ✔
Ludwigia peploides floating water primrose High ✔
Lythrum hyssopifolia hyssop loosestrife Moderate
Lythrum junceum creeping loosestrife Watch ✔
Lythrum salicaria purple loosestrife High -* ✔
Malephora crocea coppery Mesembryanthemum Watch ✔
Marrubium vulgare horehound Limited ✔
Maytenus boaria mayten Watch ✔
Medicago polymorpha California burclover Limited
Melia azedarach Chinaberry tree Watch ✔
Melinis repens Natal grass Watch ✔
Mentha pulegium pennyroyal Moderate ✔
Mesembryanthemum crystallinum crystalline iceplant Moderate◆ ✔
Mesembryanthemum nodiflorum slenderleaf iceplant Limited
Myoporum laetum ngaio tree Moderate ✔
Myosotis latifolia common forget-me-not Limited ✔
Myriophyllum aquaticum parrotfeather High C ✔
Myriophyllum spicatum spike watermilfoil High
Nardus stricta matgrass Watch
Nicotiana glauca tree tobacco Moderate ✔
Nothoscordum gracile false garlic Watch -*
Olea europaea olive Limited ✔
Oncosiphon pilulifer stinknet High Q
Ononis alopecuroides foxtail restharrow Limited -*
Onopordum acanthium Scotch thistle High -* ✔
Onopordum illyricum Illyerian thistle Watch -*
Orobanche aegyptiaca Egyptian broomrape Watch A
Oxalis pes-caprae Bermuda buttercup Moderate
Paraserianthes lophantha plume Acacia Watch
Parentucellia viscosa yellow 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 Watch ✔
Pennisetum clandestinum Kikuyu grass Limited C*
Pennisetum setaceum crimson fountain grass Moderate ✔
Pennisetum villosum feathertop Watch ✔
Persicaria wallichii Himalayan knotweed Watch -* ✔
Phalaris aquatica harding grass Moderate ✔
Phoenix canariensis Canary Island date palm Limited ✔
Phytolacca americana common pokeweed Limited ✔
Pittosporum undulatum Victorian box Watch ✔
Plantago lanceolata English plantain Limited ✔
Plecostachys serpyllifolia petite-licorice Watch ✔
Poa pratensis Kentucky bluegrass Limited ✔
Polygala myrtifolia myrtle-leaf milkwort Watch
Polypogon monspeliensis rabbitsfoot grass Limited
Potamogeton crispus curly-leaved pondweed Moderate
Potentilla recta sulphur cinquefoil Watch -* ✔
Prunus cerasifera cherry plum Limited ✔
Pyracantha angustifolia narrowleaf firethorn Limited ✔
Pyracantha coccinea scarlet firethorn Limited
Pyracantha crenulata Nepalese 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 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 Limited
Saccharum ravennae ravennagrass 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 Moderate
Salsola tragus Russian thistle Limited C*
Salvia aethiopis Mediterranean sage Limited -* ✔
Salvinia molesta giant Salvinia High -*
Saponaria officinalis bouncing-bet Limited ✔
Scabiosa atropurpurea pincushion flower Watch ✔
Schinus molle Peruvian peppertree Limited ✔
Schinus terebinthifolia Brazilian pepper tree Moderate◆ ✔
Schismus arabicus Mediterranean grass Limited
Schismus barbatus common Mediterranean grass Limited
Scolymus hispanicus goldenthistle Watch -*
Senecio elegans redpurple ragwort Watch ✔
Senecio glomeratus cutleaf burnweed Moderate
Senecio jacobaea tansy ragwort Limited -*
Senecio linearifolius fireweed groundsel Watch -*
Sesbania punicea scarlet Wisteria High -* ✔
Silybum marianum milk thistle Limited ✔
Sinapis arvensis wild mustard 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 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 Moderate◆
Stipa manicata Andean tussockgrass Limited
Stipa miliacea var. miliacea smilo grass Limited
Stipa tenuissima Mexican feathergrass Watch ✔
Tamarix aphylla athel Limited B ✔
Tamarix chinensis Chinese tamarisk High -*
Tamarix gallica French tamarisk High -*
Tamarix parviflora smallflower tamarisk High -* ✔
Tamarix ramosissima saltcedar High -* ✔
Tanacetum vulgare common tansy Moderate ✔
Tetragonia tetragonioides New Zealand spinach Limited
Thinopyrum junceiforme Russian wheatgrass Watch
Torilis arvensis hedgeparsley Moderate
Triadica sebifera Chinese tallow tree Moderate◆ ✔
Tribulus terrestris puncture vine Limited -*
Trifolium hirtum rose clover Limited
Ulex europaeus gorse High -*
Undaria pinnatifida wakame Limited
Ventenata dubia North Africa grass Watch
Verbascum thapsus woolly mullein Limited ✔
Verbena bonariensis tall vervain Watch ✔
Vinca major periwinkle Moderate ✔
Volutaria tubuliflora desert knapweed Limited◆A*
Washingtonia robusta Mexican fan palm Moderate◆ ✔
Watsonia meriana bulbil Watsonia Limited ✔
Zantedeschia aethiopica calla lily Limited ✔
Zostera japonica dwarf eelgrass Moderate◆-*
Zygophyllum fabago Syrian beancaper Watch -*