Source: California Invasive Plant Council


URL of this page: http://www.cal-ipc.org/ip/inventory/updatePRE.php

Invasive Plant Inventory - 2017 Update, "Watch" plants added

The Project Team reviewed 200 plant species to evaluate the risk of each plant species becoming invasive in California in the future. These are mostly plant species that have been reported as growing outside cultivation in California and have aroused land manager concern, but which have not to-date had sufficient impact to warrent assessment using the PAF. The predictive risk assessment criteria categorizes each species as either "high-risk", "low-risk", or "evaluate further" (meaning the level of risk is indeterminate). The risk assessment tool is based on 20 criteria scored by experts using documented sources. Some criteria consider a plant's invasive behavior elsewhere in the world, especially if the area has a climate similar to the climate in at least part of California. The climate matching is based on ecological zones, plant hardiness zones, and annual precipitation. See our climate matching maps for places worldwide whose climate matches the climate in some parts of California.

Those plant species that scored in the "high-risk" category have been added to the Inventory as "watch" species. These are listed below, with links to each plant's detailed assessment. Species that scored as "low-risk" and "evaluate further" are now included on a list of species that have been assessed and are not being added to the Inventory. See the full table showing all the species assessed with scores, confidence levels, and notes from experts.

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Acacia baileyana, cootamundra wattle

Acacia cyclops, cyclops acacia

Acacia paradoxa, kangaroothorn

Acacia pycnantha, golden wattle

Acaena novae-zelandiae, biddy-biddy

Aegilops cylindrica, jointed goatgrass

Alopecurus pratensis, meadow foxtail

Alyssum murale, yellowtuft

Ambrosia trifida, giant ragweed

Araujia sericifera, bladderflower

Berberis darwinii, Darwin barberry

Berteroa incana, Hoary alyssum

Buddleja davidii, butterfly bush

Carex pendula, hanging sedge

Casuarina equisetifolia, beach sheoak

Catharanthus roseus, pink periwinkle, Madagascar periwinkle

Cenchrus echinatus, Southern Sandbur

Cenchrus longispinus, mat sandbur

Centaurea diluta, N. African knapweed

Cestrum parqui, willow jessamine

Chasmanthe floribunda, African cornflag

Cytisus multiflorus, white spanishbroom

Cytisus palmensis, tagasaste

Datura inoxia, pricklyburr

Dipogon lignosus, okie bean

Dipsacus laciniatus, cutleaf teasel

Dittrichia viscosa, false yellowhead

Echium plantagineum, Patterson's curse

Elymus farctus, Russian wheatgrass

Eucalyptus cladocalyx, sugargum

Euphorbia lathyris, caper spurge

Fallopia ×bohemica, Bohemian knotweed (X Japanese and Giant)

Galega officinalis, professorweed

Genista linifolia, Mediterranean broom

Geranium lucidum, shining geranium

Grevillea robusta, silkoak

Gunnera tinctoria, Chilean gunnera

Gypsophila paniculata, baby's breath

Helianthus tuberosus, Jerusalem artichoke

Heliotropium amplexicaule, clasping or blue heliotrope

Heracleum mantegazzianum, giant hogweed

Hyparrhenia hirta, Tambookie grass

Hypericum androsaemum, sweet-amber

Hypericum grandifolium, large-leaved hypericum

Ipomoea indica, blue morningglory

Kniphofia uvaria, redhot poker

Lantana camara, lantana

Leptospermum laevigatum, Australian tea tree

Malephora crocea, coppery mesembryanthemum

Maytenus boaria, mayten

Nardus stricta, matgrass

Nothoscordum gracile, false garlic

Oncosiphon piluliferum, globe chamomile

Onopordum illyricum, Illyerian thistle

Orobanche aegyptiaca, Egyptian broomrape

Paraserianthes lophantha, plume acacia

Parthenium hysterophorus, Santa Maria feverfew

Paspalum urvillei, Vasey's grass

Paspalum vaginatum, seashore paspalum

Passiflora tarminiana, banana passionfruit

Peganum harmala, African-rue, harmel

Pennisetum villosum, feathertop

Persicaria wallichii, Himalayan knotweed

Pittosporum undulatum, Victorian box

Plecostachys serpyllifolia, petite-licorice

Polygala myrtifolia, myrtle-leaf milkwort

Pyrus calleryana, Callery pear

Rhamnus alaternus, Italian buckthorn

Romulea rosea, rosy sandcrocus

Rytidosperma caespitosum, wallabygrass

Salpichroa origanifolia, lily of the valley vine

Salsola ryanii, (no common name)

Salsola soda, glasswort

Salvia aethiopis, mediterranean sage

Scabiosa atropurpurea, pincushion flower

Scolymus hispanicus, goldenthistle

Senecio linearifolius, fireweed groundsel

Solanum aviculare, New Zealand nightshade

Solanum carolinense, Carolina horsenettle

Sphaerophysa salsula, alkali swainsonpea

Stipa brachychaeta, punagrass

Stipa tenuissima, Mexican feathergrass

Tamarix chinensis, five-stamen tamarisk

Ventenata dubia, North Africa grass

Verbena bonariensis, tall vervain

Zygophyllum fabago, Syrian beancaper