Invasive plants regulated in Connecticut (60 species, cited)

Invasive plants regulated in Connecticut

Connecticut regulates 60 invasive plants under Conn. Gen. Stat. 22a-381d (as amended by P.A. 24-11). The table below reproduces that list in full, showing each plant's status in the state's own words. Connecticut's list is a trade restriction, which governs what may be sold, propagated, or moved within the state.

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].

5 of these plants are 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 Connecticut 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. 53 of the 60 plants below carry both: Connecticut names them in statute and GRIIS lists them as invasive in the United States. The other 7 are regulated by Connecticut 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	Connecticut’s determination
Amur Honeysuckle	Lonicera maackii	Prohibited Invasive	Connecticut lists Amur Honeysuckle as a prohibited invasive plant.
Asiatic Tearthumb	Polygonum perfoliatum	Prohibited Invasive	Connecticut lists Asiatic Tearthumb as a prohibited invasive plant.
Autumn Olive	Elaeagnus umbellata	Prohibited Invasive	Connecticut lists Autumn Olive as a prohibited invasive plant.
Bolleana Poplar	Populus alba 'Pyramidalis'	Prohibited Invasive	Connecticut lists Bolleana Poplar as a prohibited invasive plant.
Brazilian Waterweed	Egeria densa	Prohibited Invasive	Connecticut lists Brazilian Waterweed as a prohibited invasive plant.
Broadleaved Pepperweed	Lepidium latifolium	Prohibited Invasive	Connecticut lists Broadleaved Pepperweed as a prohibited invasive plant.
Burningbush	Bassia scoparia	Prohibited Invasive	Connecticut lists Burningbush as a prohibited invasive plant.
Canada Bluegrass	Poa compressa	Prohibited Invasive	Connecticut lists Canada Bluegrass as a prohibited invasive plant.
Canada Thistle	Cirsium arvense	Prohibited Invasive	Connecticut lists Canada Thistle as a prohibited invasive plant.
Carolina Fanwort US native	Cabomba caroliniana	Prohibited	Connecticut lists Carolina Fanwort as a prohibited invasive plant.
Cheatgrass	Bromus tectorum	Prohibited Invasive	Connecticut lists Cheatgrass as a prohibited invasive plant.
Climbing Nightshade	Solanum dulcamara	Prohibited Invasive	Connecticut lists Climbing Nightshade as a prohibited invasive plant.
Coltsfoot	Tussilago farfara	Prohibited Invasive	Connecticut lists Coltsfoot as a prohibited invasive plant.
Common Barberry	Berberis vulgaris	Prohibited Invasive	Connecticut lists Common Barberry as a prohibited invasive plant.
Common Buckthorn	Rhamnus cathartica	Prohibited Invasive	Connecticut lists Common Buckthorn as a prohibited invasive plant.
Common Reed	Phragmites australis	Prohibited	Connecticut lists Common Reed as a prohibited invasive plant.
Common Sheep Sorrel	Rumex acetosella	Prohibited Invasive	Connecticut lists Common Sheep Sorrel as a prohibited invasive plant.
Crested Latesummer Mint	Elsholtzia ciliata	Prohibited Invasive	Connecticut lists Crested Latesummer Mint as a prohibited invasive plant.
Cup Plant US native	Silphium perfoliatum	Prohibited	Connecticut lists Cup Plant as a prohibited invasive plant.
Curly Pondweed	Potamogeton crispus	Prohibited Invasive	Connecticut lists Curly Pondweed as a prohibited invasive plant.
Cypress Spurge	Euphorbia cyparissias	Prohibited Invasive	Connecticut lists Cypress Spurge as a prohibited invasive plant.
Dames Rocket	Hesperis matronalis	Prohibited Invasive	Connecticut lists Dames Rocket as a prohibited invasive plant.
Empress Tree	Paulownia tomentosa	Prohibited Invasive	Connecticut lists Empress Tree as a prohibited invasive plant.
Eurasian Watermilfoil	Myriophyllum spicatum	Prohibited Invasive	Connecticut lists Eurasian Watermilfoil as a prohibited invasive plant.
European Swallow-Wort	Cynanchum rossicum	Prohibited Invasive	Connecticut lists European Swallow-Wort as a prohibited invasive plant.
False Indigobush US native	Amorpha fruticosa	Prohibited	Connecticut lists False Indigobush as a prohibited invasive plant.
Fig Buttercup	Ranunculus ficaria	Prohibited Invasive	Connecticut lists Fig Buttercup as a prohibited invasive plant.
Garden Valerian	Valeriana officinalis	Prohibited Invasive	Connecticut lists Garden Valerian as a prohibited invasive plant.
Garlic Mustard	Alliaria petiolata	Prohibited Invasive	Connecticut lists Garlic Mustard as a prohibited invasive plant.
Giant Hogweed	Heracleum mantegazzianum	Prohibited Invasive	Connecticut lists Giant Hogweed as a prohibited invasive plant.
Giant Knotweed	Polygonum sachalinense	Prohibited Invasive	Connecticut lists Giant Knotweed as a prohibited invasive plant.
Ground Ivy	Glechoma hederacea	Prohibited Invasive	Connecticut lists Ground Ivy as a prohibited invasive plant.
Japanese Hop	Humulus japonicus	Prohibited Invasive	Connecticut lists Japanese Hop as a prohibited invasive plant.
Japanese Knotweed	Polygonum cuspidatum	Prohibited	Connecticut lists Japanese Knotweed as a prohibited invasive plant.
Japanese Sedge	Carex kobomugi	Prohibited Invasive	Connecticut lists Japanese Sedge as a prohibited invasive plant.
Jimsonweed	Datura stramonium	Prohibited Invasive	Connecticut lists Jimsonweed as a prohibited invasive plant.
Kudzu	Pueraria montana	Prohibited Invasive	Connecticut lists Kudzu as a prohibited invasive plant.
Leafy Spurge	Euphorbia esula	Prohibited Invasive	Connecticut lists Leafy Spurge as a prohibited invasive plant.
Louise's Swallow-Wort	Cynanchum louiseae	Prohibited Invasive	Connecticut lists Louise's Swallow-Wort as a prohibited invasive plant.
Morrow's Honeysuckle	Lonicera morrowii	Prohibited Invasive	Connecticut lists Morrow's Honeysuckle as a prohibited invasive plant.
Multiflora Rose	Rosa multiflora	Prohibited Invasive	Connecticut lists Multiflora Rose as a prohibited invasive plant.
Narrowleaf Bittercress	Cardamine impatiens	Prohibited Invasive	Connecticut lists Narrowleaf Bittercress as a prohibited invasive plant.
Nepalese Browntop	Microstegium vimineum	Prohibited Invasive	Connecticut lists Nepalese Browntop as a prohibited invasive plant.
Oriental Bittersweet	Celastrus orbiculatus	Prohibited Invasive	Connecticut lists Oriental Bittersweet as a prohibited invasive plant.
Ornamental Jewelweed	Impatiens glandulifera	Prohibited Invasive	Connecticut lists Ornamental Jewelweed as a prohibited invasive plant.
Ragged Robin	Lychnis flos-cuculi	Prohibited Invasive	Connecticut lists Ragged Robin as a prohibited invasive plant.
Russian Olive	Elaeagnus angustifolia	Prohibited Invasive	Connecticut lists Russian Olive as a prohibited invasive plant.
Scotch Cottonthistle	Onopordum acanthium	Prohibited Invasive	Connecticut lists Scotch Cottonthistle as a prohibited invasive plant.
Showy Fly Honeysuckle	Lonicera x bella	Prohibited Invasive	Connecticut lists Showy Fly Honeysuckle as a prohibited invasive plant.
Slender Snakecotton US native	Froelichia gracilis	Prohibited	Connecticut lists Slender Snakecotton as a prohibited invasive plant.
Small Carpetgrass	Arthraxon hispidus	Prohibited Invasive	Connecticut lists Small Carpetgrass as a prohibited invasive plant.
Spotted Knapweed	Centaurea stoebe subsp. micranthos	Prohibited Invasive	Connecticut lists Spotted Knapweed as a prohibited invasive plant.
Stinking Willie	Senecio jacobaea	Prohibited Invasive	Connecticut lists Stinking Willie as a prohibited invasive plant.
Sycamore Maple	Acer pseudoplatanus	Prohibited Invasive	Connecticut lists Sycamore Maple as a prohibited invasive plant.
Tree of Heaven	Ailanthus altissima	Prohibited Invasive	Connecticut lists Tree of Heaven as a prohibited invasive plant.
Twoleaf Watermilfoil US native	Myriophyllum heterophyllum	Prohibited	Connecticut lists Twoleaf Watermilfoil as a prohibited invasive plant.
Variegated Water Grass	Glyceria maxima 'Variegata'	Prohibited Invasive	Connecticut lists Variegated Water Grass as a prohibited invasive plant.
Water Chestnut	Trapa natans	Prohibited Invasive	Connecticut lists Water Chestnut as a prohibited invasive plant.
Waterthyme	Hydrilla verticillata	Prohibited Invasive	Connecticut lists Waterthyme as a prohibited invasive plant.
Wine Raspberry	Rubus phoenicolasius	Prohibited Invasive	Connecticut lists Wine Raspberry as a prohibited invasive plant.

What the tags mean

Prohibited Restricted Listed

A legal status. Connecticut 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 Connecticut’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

Connecticut listings: Conn. Gen. Stat. 22a-381d (as amended by P.A. 24-11). 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 Connecticut’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 Connecticut

Plants that two or more states bordering Connecticut regulate, and Connecticut 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.

Amur Corktree Phellodendron amurense regulated in Massachusetts, New York
Black Locust Robinia pseudoacacia regulated in Massachusetts, New York
Blueberry Creeper Ampelopsis brevipedunculata regulated in Massachusetts, New York
Border Privet Ligustrum obtusifolium regulated in Massachusetts, New York
Burning Bush Euonymus alatus regulated in Massachusetts, New York
Japanese Angelica Tree Aralia elata regulated in Massachusetts, New York
Japanese Barberry Berberis thunbergii regulated in Massachusetts, New York
Japanese Honeysuckle Lonicera japonica regulated in Massachusetts, New York
Japanese Knotweed Fallopia japonica (potentially invasive weed) regulated in Massachusetts, New York
Large Gray Willow Salix atrocinerea regulated in Massachusetts, New York
Maiden Grass Miscanthus sinensis regulated in Massachusetts, New York
Norway Maple Acer platanoides regulated in Massachusetts, New York
Paleyellow Iris Iris pseudacorus regulated in Massachusetts, New York
Parrot Feather Watermilfoil Myriophyllum aquaticum regulated in Massachusetts, New York
Purple Loosestrife Lythrum salicaria regulated in Massachusetts, New York

Questions

What plants are illegal to sell in Connecticut?

60 plants are regulated under Conn. Gen. Stat. 22a-381d (as amended by P.A. 24-11). Plants marked Prohibited may not be sold, propagated, or moved within Connecticut. Plants marked Restricted carry narrower limits set by the rule.

Is my plant invasive in Connecticut?

Search the table on this page, or enter the plant's name in Ezina's checker to get its Connecticut 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 Connecticut?

No. This page reproduces what Connecticut 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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