Click on the plant name to learn more about the species. Not all invasive plants are listed on this page. If you are looking for a particular plant, you can use the search bar at the top of this page.

The PEI Invasive Species Council has drafted a prioritized list of invasive plants for the province. Council members prioritized species on this list using the B.C. Invasive Plant Core Ranking Process. Click the thumbnail below to access the Draft PEI Invasive Alien Species Plant List.

The species listed in RED are highest priority and species listed in BLUE are not yet present in PEI – if you spot one of these species, please report it right away. This list is a work on progress, it does not include all of the invasive species on PEI.

PEI Draft IS Plant List

Wild Parsnip (Pastinaca sativa)

Wild parsnip, also known as poison parsnip, is native to Europe and Asia.  The plant’s root resembles the domestic parsnip and is also edible.  It’s likely that it was brought to North America by European settlers as a food source.  Wild parsnip is related to giant hogweed and shares some similar properties, including sap that […]

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Common Reed Grass (Phragmites australis ssp. australis)

Common reed grass (Phragmites australis ssp. australis) is an invasive perennial grass that is native to Eurasia.  It is not known for certain how it was moved to North America, but it likely arrived on the Atlantic coast accidentally via ballast materials in the late 1700s – early 1800s.  (Swearingen, J. and K. Saltonstall. 2010) […]

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Canada Waterweed (Elodea canadensis)

Canada waterweed is an underwater perennial.  It grows in dense mats in clear waters.  Most people know it as an aquarium plant.  It is considered native to Nova Scotia and New Brunswick, but outcompetes native pond weeds in Island waterbodies.  Canada waterweed was first detected in PEI at Knox’s Damn, Head of Montague, in 2005, […]

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Cypress Spurge (Euphorbia cyparissias)

Cypress spurge is a herbaceous perennial plant.  It grows in open, disturbed areas such as pastures, abandoned fields, ditches and coastal areas.   IDENTIFICATION Here are some key features that may help to positively identify cypress spurge: Can grow to 10-40cm tall Leaves are small, linear-shaped, 1-3cm long and 1-3mm wide, whorled around the stem […]

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Blackthorn (Prunus spinosa)

Blackthorn is a small, deciduous shrubby tree.  It grows best in moist, well drained soils and full sun.  It is native to most of Europe, the UK and Western Asia.  It is often referred to as “sloe”.  It has a native lookalike on PEI, Hawthorn (Crataegus spp.).  However, blackthorn spines have buds growing along their […]

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Black Knapweed (Centaurea nigra)

Black Knapweed is a perennial plant native to the Meditarranean, but is also naturalized throughout Europe.  Black Knapweed was first introduced to North America in the early 1900s as an ornamental species, and is now present is most Canadian provinces.  It tolerates a wide range of conditions and habitats, however it grows best in disturbed, […]

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Flowering Rush (Butomus umbellatus)

  Flowering rush is an aquatic perennial that resembles our native sedge species.  It can be difficult to distinguish from native sedges, unless it is in flower.  It can grow in dense stand both in and out of water.  This species is still sometimes sold in garden centers and is readily available for purchase online. […]

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Leafy Spurge (Euphorbia esula)

  Leafy spurge is a herbaceous perennial plant.  It grows in open disturbed areas such as pastures, abandoned fields, ditches and coastal areas.  It is native to central and southern Europe.  All parts of the plant contain a milky latex (sap) that can irritate livestock and cause rashes and skin irritations in humans.     […]

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Sycamore Maple (Acer pseudoplatanus)

  Sycamore Maple is a deciduous tree species that can reach 20m in height.  It is a very adaptable species that grows in full sun or light shade, and tolerates some salt.  It is native to Europe and western Asia.       IDENTIFICATION Here are some key features that may help to positively identify […]

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Oriental Bittersweet (Celastrus orbiculatus)

Oriental Bittersweet is a deciduous, woody vine.  It can be found growing in woodlands, forest edges, grasslands, roadsides, hedgerows – essentially anywhere except in wet areas.  This species’ generalist approach means that Oriental Bittersweet has an increased probability of finding suitable habitat to establish and invade.     IDENTIFICATION Here are some key features that […]

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Woodland Angelica (Angelica sylvestris)

Woodland Angelica will tolerate full sunlight or full shade, but prefers moist soils. It is often found growing in disturbed roadside habitats, forest edges and open moist areas. IDENTIFICATION Here are some key features that may help to positively identify Woodland Angelica: A robust plant, growing up to 2m tall Stem is bamboo-like, sparsely branched, […]

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Common Valerian (Valeriana officinalis)

Common Valerian grows in moist soils, along stream banks, in wet meadows, fens, and roadside ditches.  It can also grow in dryer conditions, and will tolerate some shade.   HISTORY Common Valerian was brought to North America as a garden and medicinal plant.  It is still cultivated for these purposes, but often manages to escape […]

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Bittersweet Nightshade (Solanum dulcamara)

  Bittersweet nightshade is a perennial, climbing vine. It grows in a wide range of habitats but prefers not to be in full sun. It can be found growing along hedgerows, forest edges, riparian zones and in forest understories. Its stems and berries have been used in herbalism to treat skin conditions such as herpes […]

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Periwinkle (Vinca minor)

  Periwinkle can be found trailing along the ground in forests and other shaded areas. Periwinkle spreads very quickly and can cover large areas. It can choke out native species that inhabit the same space and greatly reduce the biodiversity of an area.

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Wild Cucumber (Echinocystis lobata)

  Wild Cucumber grows along trails, in fields, on the edges of forests and in riparian zones across PEI. Wild cucumber is a vine that grows on other shrubs and trees and can choke out smaller plants. It is easy to spot thanks to its prickly, cucumber-like fruit.

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Scotch Broom (Cytisus scoparius)

  Scotch Broom grows in open areas, in ditches, meadows and yards. It competes with native species for available light, nutrients and moisture and has no natural enemies on PEI. It has a deep and extensive root system so it is very difficult to eradicate once it becomes established. Fortunately, Scotch broom is not yet […]

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Japanese Knotweed (Fallopia japonica)

  Japanese Knotweed is one of the Global Invasive Species Database’s 100 worst invaders. It grows in a wide variety of habitats and tolerates a wide range of adverse conditions such as deep shade, high temperatures, salinity, and drought. It grows in dense thickets that shade out neighbouring species and spreads readily via underground rhizomes. […]

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Multiflora Rose (Rosa multiflora)

  Multiflora Rose has a wide tolerance for various soil, moisture, and light conditions. It occurs in dense woods, along stream banks and roadsides and in open fields and pastures.  Multiflora rose is extremely prolific and can form impenetrable thickets that exclude native plant species.  Multiflora Rose is relatively widespread across PEI.   HISTORY Originally […]

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Purple Loosestrife (Lythrum salicaria)

  Purple loosestrife invades and destroys habitat along rivers, streams, and wetlands. It grows in dense patches that choke out native plants and deter wildlife. Purple loosestrife is a prolific seed producer and its light seeds are carried by wind and often take hold in nearby wetlands.

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Garlic Mustard (Alliaria petiolata)

Garlic Mustard tolerates shade and grows in rich moist areas, which makes this plant of particular concern since it is commonly found invading woodlands. It can outcompete native flowering woodland plants like Sweet Cicely, Dutchman’s Breeches and violets. Fortunately, Garlic Mustard is not yet widespread on PEI. We hope to keep it that way!   […]

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Common Buckthorn (Rhamnus cathartica)

Common Buckthorn tolerates a wide range of upland habitats including forests and riparian zones. Common Buckthorn outcompetes native species through a variety of mechanisms. It forms a dense canopy layer that readily shades out surrounding species, and it secretes a chemical from its roots that is poisonous to other plants. Common Buckthorn is not as […]

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Yellow Flag Iris (Iris pseudacorus)

  Yellow Flag Iris grows in wet areas such as ditches, wetlands and around streams and ponds. It is an aggressive invader that forms dense thickets that prevent the growth of native plants. Infestations can impact amphibians, birds, and other wetland wildlife. Wetland plants are especially difficult to eradicate once established. Prevention is the only […]

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Giant Hogweed (Heracleum mantegazzianum)

  Giant Hogweed is generally found along roadsides, in ditches, along streambanks and in disturbed waste areas. The clear watery sap of Giant hogweed contains toxins that can cause severe dermatitis. UV radiation activates compounds in the sap resulting in severe burns when exposed to the sun. Symptoms occur within 48 hours and consist of […]

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Glossy Buckthorn (Frangula alnus)

HISTORY Glossy Buckthorn was introduced from Europe as an ornamental shrub. It is a very aggressive and invasive shrub with multiple stems and can grow to be twenty feet tall. Glossy Buckthorn tolerates a wide range of habitats from wetlands to woodland edges, old fields, ditches and grassy areas. Distribution is mostly by sexual reproduction […]

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Himalayan Balsam (Impatiens glandulifera)

  Himalayan Balsam is incredibly invasive in moist areas such as ditches and along streams. Himalayan Balsam can outcompete native riparian species and when it dies back in the fall it leaves streambanks susceptible to erosion.

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