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

Invasive plants regulated in Pennsylvania

Pennsylvania regulates 57 invasive plants under 3 Pa.C.S. 1501-1562 (Act 46 of 2017). The table below reproduces that list in full, showing each plant's status in the state's own words. Pennsylvania'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].

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2 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 Pennsylvania 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. 49 of the 57 plants below carry both: Pennsylvania names them in statute and GRIIS lists them as invasive in the United States. The other 8 are regulated by Pennsylvania 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 Pennsylvania’s determination
Amur Honeysuckle Lonicera maackii Prohibited Invasive Pennsylvania lists Amur Honeysuckle under “Class B.”Plant instead: Hercules's Club, Rough-Leaf Dogwood, Common Witch Hazel
Animated Oat Avena sterilis Prohibited Invasive Pennsylvania lists Animated Oat under “Class A.”
Asiatic Tearthumb Polygonum perfoliatum Prohibited Invasive Pennsylvania lists Asiatic Tearthumb under “Class B.”
Basketgrass Oplismenus hirtellus Prohibited Pennsylvania lists Basketgrass under “Class A.”
Blood Grass Imperata cylindrica Prohibited Invasive Pennsylvania lists Blood Grass under “Class A.”Plant instead: Little Green Sedge, Lopsided Rush, Kentucky Bluegrass
Bohemian Knotweed Polygonum x bohemicum Prohibited Pennsylvania lists Bohemian Knotweed under “Class B.”
Border Privet Ligustrum obtusifolium Prohibited Invasive Pennsylvania lists Border Privet under “Class B.”Plant instead: Crimsoneyed Rosemallow, Bushy St. Johnswort, New York Ironweed
Brazilian Waterweed Egeria densa Prohibited Invasive Pennsylvania lists Brazilian Waterweed under “Class A.”Plant instead: Star Sedge, Geyer's Sedge, Inland Sedge
Bull Thistle Cirsium vulgare Prohibited Invasive Pennsylvania lists Bull Thistle under “Class B.”
Burning Bush Euonymus alatus Prohibited Invasive Pennsylvania lists Burning Bush under “Class B.”Plant instead: New York Ironweed, Hairy Lespedeza, American Black Elderberry
Callery Pear Pyrus calleryana Prohibited Invasive Pennsylvania lists Callery Pear under “Class B.”Plant instead: Western Catalpa, Paper Birch, Cockspur Hawthorn
Canada Thistle Cirsium arvense Prohibited Invasive Pennsylvania lists Canada Thistle under “Class B.”
Carelessweed US native Amaranthus palmeri Prohibited Pennsylvania lists Carelessweed under “Class A.”
Common Buckthorn Rhamnus cathartica Prohibited Invasive Pennsylvania lists Common Buckthorn under “Class B.”Plant instead: Hercules's Club, Rough-Leaf Dogwood, Common Witch Hazel
Common Frogbit Hydrocharis morsus-ranae Prohibited Invasive Pennsylvania lists Common Frogbit under “Class A.”
Common Wormwood Artemisia vulgaris Prohibited Invasive Pennsylvania lists Common Wormwood under “Class B.”Plant instead: Coast Cockspur Grass, Crimsoneyed Rosemallow, Common Rush
Eurasian Watermilfoil Myriophyllum spicatum Prohibited Invasive Pennsylvania lists Eurasian Watermilfoil under “Class B.”
European Swallow-Wort Cynanchum rossicum Prohibited Invasive Pennsylvania lists European Swallow-Wort under “Class B.”
European Wand Loosestrife Lythrum virgatum Prohibited Pennsylvania lists European Wand Loosestrife under “Class B.”Plant instead: Crimsoneyed Rosemallow, Hairy Lespedeza, American Black Elderberry
Fig Buttercup Ranunculus ficaria Prohibited Invasive Pennsylvania lists Fig Buttercup under “Class B.”Plant instead: Common Selfheal, Meadow Evening Primrose, Northern St. Johnswort
Fiveleaf Akebia Akebia quinata Prohibited Invasive Pennsylvania lists Fiveleaf Akebia under “Class A.”
Garlic Mustard Alliaria petiolata Prohibited Invasive Pennsylvania lists Garlic Mustard under “Class B.”
Giant Hogweed Heracleum mantegazzianum Prohibited Invasive Pennsylvania lists Giant Hogweed under “Class A.”
Giant Knotweed Polygonum sachalinense Prohibited Invasive Pennsylvania lists Giant Knotweed under “Class B.”
Glossy Buckthorn Frangula alnus Prohibited Invasive Pennsylvania lists Glossy Buckthorn under “Class B.”Plant instead: Rough-Leaf Dogwood, Common Witch Hazel, Canadian Serviceberry
Japanese Angelica Tree Aralia elata Prohibited Invasive Pennsylvania lists Japanese Angelica Tree under “Class B.”Plant instead: Yellow Passionflower, American Plum, Climbing Rose
Japanese Barberry Berberis thunbergii Prohibited Invasive Pennsylvania lists Japanese Barberry under “Class B.”Plant instead: Crimsoneyed Rosemallow, Bushy St. Johnswort, New York Ironweed
Japanese Hop Humulus japonicus Prohibited Invasive Pennsylvania lists Japanese Hop under “Class B.”
Japanese Knotweed Fallopia japonica (potentially invasive weed) Prohibited Invasive Pennsylvania lists Japanese Knotweed under “Class B.”
Japanese Privet Ligustrum japonicum Prohibited Invasive Pennsylvania lists Japanese Privet under “Class A.”
Johnsongrass Sorghum halepense Prohibited Invasive Pennsylvania lists Johnsongrass under “Class B.”
Large-Flower Primrose-Willow Ludwigia grandiflora Prohibited Invasive Pennsylvania lists Large-Flower Primrose-Willow under “Class A.”
Louise's Swallow-Wort Cynanchum louiseae Prohibited Invasive Pennsylvania lists Louise's Swallow-Wort under “Class B.”
Morrow's Honeysuckle Lonicera morrowii Prohibited Invasive Pennsylvania lists Morrow's Honeysuckle under “Class B.”Plant instead: Crimsoneyed Rosemallow, Bushy St. Johnswort, New York Ironweed
Multiflora Rose Rosa multiflora Prohibited Invasive Pennsylvania lists Multiflora Rose under “Class B.”Plant instead: Crimsoneyed Rosemallow, Hairy Lespedeza, American Black Elderberry
Nepalese Browntop Microstegium vimineum Prohibited Invasive Pennsylvania lists Nepalese Browntop under “Class B.”
Nodding Plumeless Thistle Carduus nutans Prohibited Invasive Pennsylvania lists Nodding Plumeless Thistle under “Class B.”
Oriental Bittersweet Celastrus orbiculatus Prohibited Invasive Pennsylvania lists Oriental Bittersweet under “Class B.”Plant instead: Rough-Leaf Dogwood, Common Witch Hazel, Canadian Serviceberry
Parrot Feather Watermilfoil Myriophyllum aquaticum Prohibited Invasive Pennsylvania lists Parrot Feather Watermilfoil under “Class A.”Plant instead: Velvet Bentgrass, Little Green Sedge, Lopsided Rush
Parsnip Pastinaca sativa Prohibited Invasive Pennsylvania lists Parsnip under “Class B.”
Plume Grass Saccharum ravennae (Erianthus ravennae) Prohibited Pennsylvania lists Plume Grass under “Class A.”
Poison Hemlock Conium maculatum Prohibited Invasive Pennsylvania lists Poison Hemlock under “Class B.”
Professor-Weed Galega officinalis Prohibited Invasive Pennsylvania lists Professor-Weed under “Class A.”
Purple Loosestrife Lythrum salicaria Prohibited Invasive Pennsylvania lists Purple Loosestrife under “Class B.”Plant instead: Crimsoneyed Rosemallow, Hairy Lespedeza, American Black Elderberry
Roughfruit Amaranth US native Amaranthus tuberculatus Prohibited Pennsylvania lists Roughfruit Amaranth under “Class A.”
Showy Fly Honeysuckle Lonicera x bella Prohibited Invasive Pennsylvania lists Showy Fly Honeysuckle under “Class B.”Plant instead: Crimsoneyed Rosemallow, Bushy St. Johnswort, New York Ironweed
Sorghum Sorghum bicolor Prohibited Invasive Pennsylvania lists Sorghum under “Class B.”
Standish's Honeysuckle Lonicera standishii Prohibited Pennsylvania lists Standish's Honeysuckle under “Class B.”
Sunshine Chinese Privet Ligustrum sinense 'Sunshine' Prohibited Invasive Pennsylvania lists Sunshine Chinese Privet under “Class B.”
Tatarian Honeysuckle Lonicera tatarica Prohibited Invasive Pennsylvania lists Tatarian Honeysuckle under “Class B.”Plant instead: Crimsoneyed Rosemallow, Hairy Lespedeza, American Black Elderberry
Tree of Heaven Ailanthus altissima Prohibited Invasive Pennsylvania lists Tree of Heaven under “Class B.”Plant instead: Table Mountain Pine, Shingle Oak, Sweet Birch
Water Chestnut Trapa natans Prohibited Invasive Pennsylvania lists Water Chestnut under “Class A.”Plant instead: Velvet Bentgrass, Little Green Sedge, Lopsided Rush
Water Soldiers Stratiotes aloides Prohibited Pennsylvania lists Water Soldiers under “Class C.”Plant instead: Velvet Bentgrass, Little Green Sedge, Lopsided Rush
Waterthyme Hydrilla verticillata Prohibited Invasive Pennsylvania lists Waterthyme under “Class B.”Plant instead: Star Sedge, Geyer's Sedge, Inland Sedge
Wild Chervil Anthriscus sylvestris Prohibited Invasive Pennsylvania lists Wild Chervil under “Class A.”
Wild Privet Ligustrum vulgare Prohibited Invasive Pennsylvania lists Wild Privet under “Class B.”Plant instead: Crimsoneyed Rosemallow, Bushy St. Johnswort, New York Ironweed
Yellow Floatingheart Nymphoides peltata Prohibited Invasive Pennsylvania lists Yellow Floatingheart under “Class A.”Plant instead: Nodding Lady's Tresses, Valley Redstem, American Vetch

What the tags mean

Prohibited Restricted Listed

A legal status. Pennsylvania 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 Pennsylvania’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

Pennsylvania listings
3 Pa.C.S. 1501-1562 (Act 46 of 2017). 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 Pennsylvania’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 Pennsylvania

Plants that two or more states bordering Pennsylvania regulate, and Pennsylvania 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 Pennsylvania?

57 plants are regulated under 3 Pa.C.S. 1501-1562 (Act 46 of 2017). Plants marked Prohibited may not be sold, propagated, or moved within Pennsylvania. Plants marked Restricted carry narrower limits set by the rule.

Is my plant invasive in Pennsylvania?

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

No. This page reproduces what Pennsylvania 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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