Ezina · A field manual for plant care · Contiguous U.S.Vol. I · Ed. 2027 · Proof copy

Invasive plants regulated in Arizona

Arizona lists 43 plants as noxious weeds under Ariz. Admin. Code R3-4-245, Tables 4-6. The table below reproduces that list in full, showing each plant's status in the state's own words. Arizona's list is an agricultural noxious-weed law, which governs control and spread on farmland and rights of way rather than what a nursery may sell.

Compiled from the rule itself, retrieved July 20, 2026. Law changes; if you spot a listing we have wrong or stale, tell us at [email protected].

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1 of these plant is native to part of the United States, marked US native below. Nativity is regional. Black locust is native to the Appalachians and regulated in New England; Palmer amaranth is native to the Southwest and listed as an agricultural weed in the Corn Belt. A listing tells you what Arizona regulates, not where a plant belongs. The county checker answers the second question.

Regulated and invasive are two different findings, and this page shows them separately. 37 of the 43 plants below carry both: Arizona names them in statute and GRIIS lists them as invasive in the United States. The other 6 are regulated by Arizona without appearing on that register. The reverse is far more common still: most plants GRIIS calls invasive are named in no state’s statute at all and are sold freely, so an absent chip is never a clean bill of health.

Plant Scientific name Status Arizona’s determination
Canada Thistle Cirsium arvense Prohibited Invasive Arizona lists Canada Thistle under “Class A.”
Cantaloupe Cucumis melo Prohibited Invasive Arizona lists Cantaloupe under “Class A.”
Common Water Hyacinth Eichhornia crassipes Prohibited Invasive Arizona lists Common Water Hyacinth under “Class A.”Plant instead: Yerba Mansa, Silvery Lupine, Yellow Owl's-Clover
Dyer's Woad Isatis tinctoria Prohibited Invasive Arizona lists Dyer's Woad under “Class A.”
Harmal Peganum Peganum harmala Prohibited Invasive Arizona lists Harmal Peganum under “Class A.”
Kariba-Weed Salvinia molesta Prohibited Invasive Arizona lists Kariba-Weed under “Class A.”
Leafy Spurge Euphorbia esula Prohibited Invasive Arizona lists Leafy Spurge under “Class A.”
Lenspod Whitetop Cardaria chalepensis Prohibited Arizona lists Lenspod Whitetop under “Class A.”
Waterthyme Hydrilla verticillata Prohibited Invasive Arizona lists Waterthyme under “Class A.”Plant instead: Inland Sedge, Analogue Sedge, Timber Oatgrass
African Sumac Searsia lancea Listed Arizona lists African Sumac under “Class B.”
Asian Mustard Brassica tournefortii Listed Invasive Arizona lists Asian Mustard under “Class B.”
Black Mustard Brassica nigra Listed Invasive Arizona lists Black Mustard under “Class B.”
Bull Thistle Cirsium vulgare Listed Invasive Arizona lists Bull Thistle under “Class B.”
Burningbush Bassia scoparia Listed Invasive Arizona lists Burningbush under “Class C.”
Cheatgrass Bromus tectorum Listed Invasive Arizona lists Cheatgrass under “Class C.”
Common Morning Glory Ipomoea purpurea Listed Invasive Arizona lists Common Morning Glory under “Class C.”
Diffuse Knapweed Centaurea diffusa Listed Invasive Arizona lists Diffuse Knapweed under “Class B.”
Field Bindweed Convolvulus arvensis Listed Invasive Arizona lists Field Bindweed under “Class C.”
Fountain Grass Pennisetum setaceum Listed Invasive Arizona lists Fountain Grass under “Class C.”
Giant Reed Arundo donax Listed Invasive Arizona lists Giant Reed under “Class B.”
Grannyvine Ipomoea tricolor Listed Arizona lists Grannyvine under “Class C.”
Hardheads Acroptilon repens Listed Invasive Arizona lists Hardheads under “Class B.”
Hemp Broomrape Orobanche ramosa Listed Arizona lists Hemp Broomrape under “Class B.”
Ivyleaf Morning-Glory Ipomoea hederacea Listed Arizona lists Ivyleaf Morning-Glory under “Class C.”
Johnsongrass Sorghum halepense Listed Invasive Arizona lists Johnsongrass under “Class C.”
Jointed Goatgrass Aegilops cylindrica Listed Invasive Arizona lists Jointed Goatgrass under “Class B.”
Lehmann Lovegrass Eragrostis lehmanniana Listed Invasive Arizona lists Lehmann Lovegrass under “Class C.”
Littlebell Ipomoea triloba Listed Invasive Arizona lists Littlebell under “Class C.”
Maltese Star-Thistle Centaurea melitensis Listed Invasive Arizona lists Maltese Star-Thistle under “Class B.”
Nodding Plumeless Thistle Carduus nutans Listed Invasive Arizona lists Nodding Plumeless Thistle under “Class B.”
Onionweed Asphodelus fistulosus Listed Invasive Arizona lists Onionweed under “Class B.”
Puncturevine Tribulus terrestris Listed Invasive Arizona lists Puncturevine under “Class C.”
Red Brome Bromus rubens Listed Invasive Arizona lists Red Brome under “Class C.”
Ripgut Brome Bromus diandrus Listed Invasive Arizona lists Ripgut Brome under “Class B.”
Rose Natal Grass Melinis repens Listed Invasive Arizona lists Rose Natal Grass under “Class B.”
Russian Olive Elaeagnus angustifolia Listed Invasive Arizona lists Russian Olive under “Class B.”Plant instead: Western Soapberry, Cerro Hawthorn, American Plum
Saltlover Halogeton glomeratus Listed Invasive Arizona lists Saltlover under “Class B.”
Scotch Cottonthistle Onopordum acanthium Listed Invasive Arizona lists Scotch Cottonthistle under “Class B.”
Siberian Elm Ulmus pumila Listed Invasive Arizona lists Siberian Elm under “Class B.”Plant instead: Arizona Walnut, Pinyon Pine, Single Leaf Pinyon Pine
Tree of Heaven Ailanthus altissima Listed Invasive Arizona lists Tree of Heaven under “Class C.”Plant instead: Arizona Walnut, Pinyon Pine, Single Leaf Pinyon Pine
Whitestar Morning-Glory US native Ipomoea x leucantha Listed Arizona lists Whitestar Morning-Glory under “Class C.”
Yellow Bluestem Bothriochloa ischaemum Listed Invasive Arizona lists Yellow Bluestem under “Class B.”
Yellow Star-Thistle Centaurea solstitialis Listed Invasive Arizona lists Yellow Star-Thistle under “Class B.”

What the tags mean

Prohibited Restricted Listed

A legal status. Arizona names the plant in statute. Under a nursery rule that means it may not be sold, propagated, or moved; under an agricultural weed law it means landowners must control it. The cited rule says which, in Arizona’s own words, in the last column.

Invasive

An ecological finding, and a different question from the law. GRIIS — the Global Register of Introduced and Invasive Species — lists the plant as invasive in the United States. Most invasive plants carry no state listing at all and are sold freely, so a plant without this tag is not thereby safe, and a plant without a legal chip is not thereby harmless.

Where this comes from

Arizona listings
Ariz. Admin. Code R3-4-245, Tables 4-6. Read the rule.
Invasive status
GRIIS, the Global Register of Introduced and Invasive Species, via GBIF. A scientific register with no legal force; it is cited separately from the statute above because the two disagree far more often than they agree.
Status wording
Each determination is written as a sentence, with Arizona’s own term for the plant reproduced verbatim inside it. The Prohibited / Restricted / Listed chips are Ezina’s normalisation across 42 states and are not the legal term.
Nativity
USDA PLANTS county distribution layer, surfaced through the county checker.

Regulated next door, but not in Arizona

Plants that two or more states bordering Arizona regulate, and Arizona does not. A listing is a legal act rather than an ecological one, so a plant can be a documented problem here and still be sold here.

Questions

What plants are illegal to sell in Arizona?

Arizona's list is an agricultural noxious-weed law, which governs control and spread on farmland and rights of way rather than what a nursery may sell. 43 plants are named under Ariz. Admin. Code R3-4-245, Tables 4-6. A noxious-weed listing does not automatically ban nursery sale, so check the rule itself before assuming a plant cannot be bought or sold.

Is my plant invasive in Arizona?

Search the table on this page, or enter the plant's name in Ezina's checker to get its Arizona status alongside whether USDA records it as native to your specific county. Every answer links the record it came from.

Does a plant missing from this list mean it is safe to plant in Arizona?

No. This page reproduces what Arizona regulates, and a state list is a legal instrument rather than an ecological verdict. Plenty of plants spread aggressively without ever being listed, and states add species years after the problem is documented.

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