Watch out for the following invasive species which have been found in BC but are not yet established in our province. Familiarize yourself with these invasive species, be on the lookout and report any suspected sightings!
Watch out for the following invasive species which have been found in BC but are not yet established in our province. Familiarize yourself with these invasive species, be on the lookout and report any suspected sightings!
The American bullfrog is the largest frog in BC olive green, with mottled brown spots on their back. Adults can grow to 18-20 cm long, not including the legs. Bullfrogs usually live in areas with warm, slow-moving water and lots of vegetation, like ponds, lakes, ditches, and slow-moving streams. They are predators with a big appetite and will eat almost anything they can fit into their mouths.
Argentine ants are a small light brown ant that are odorless when crushed. They are one of the most prolific invasive insects in the world. Although these ants are not dangerous to humans, they pose a serious threat to other ant species, and can become a serious nuisance pest in human buildings and public spaces.
Black slug (Arion ater) and Chocolate arion (Arion rufus) are two closely related invasive slugs known in BC that cannot be identified using morphological traits. Also known as red or chocolate slugs, they are native to Europe and have been introduced to many countries through human activity. This slug has been well established in BC since the 1940s and is common throughout Southern BC and Haida Gwaii.
Asian clam (Golden clam, Good luck clam) is a freshwater clam that is 2.5 cm wide, with deep, concentric ridges. They can survive in a variety of freshwater habitats, and tolerate water temperatures between 2-30 °C. They may pose a risk to water treatment facilities, irrigation canals, and dams.
Asian long-horned beetle (Starry sky, Sky beetle) is a highly destructive wood-boring insect with a white-speckled black abdomen and long, white stripped antennae. This species has not yet been found in BC but could spread long distances to other provinces or territories through transport of infested wood products like firewood and logs.
Baby’s breath (Common gypsophila) is a slender, short bush with silvery, narrow leaves and lots of tiny, star shaped white flowers. It is an escaped ornamental plant that spreads primarily through seed, with each plant having the ability to spread over 10,000 seeds. When it invades grazing land, it reduces native grasses and forage for grazing animals and wildlife.
Bachelor’s button (Cornflower) is a flowering plant that can be 1 m in height, with multiple bell-shaped blue, purple or pink marginal flower arranged around the flower head. This invasive plant produces large amounts of seed and can easily invade dry meadows, fields, and grasslands.
The Balsam wooly adelgid is a small, sap-sucking wingless insect that feeds on true Firs (Abies spp.). They damage and kill trees by feeding through their toxic saliva. Tree growth will be hindered, the crown may die, and the wood quality will be severely reduced.
Blueweed (Viper’s bugloss) is a plant that is hairy and painful to touch with bright blue flowers. It is toxic to horses and cattle and reduces forage quality in rangelands and pastures, resulting in economic losses. Plants can drop up to 2800 rough seeds that can be further spread by clinging onto animals or humans.
Bohemian knotweed is a hybrid between Japanese (Reynoutria japonica) and Giant knotweed (Reynoutria sachalinensis) and resembles both species. Knotweeds were introduced to British Columbia for use in gardens and landscaping due to their rapid growth and attractive appearance. There are now four species established in BC: Bohemian, Giant, Himalayan, and Japanese knotweed.
Brown marmorated stink bugs are small shield-shaped insects that have two small, white stripes on the ends of their antennae, and white and black spots at the base of their abdomen. They were first seen in BC in 2016. They have become a serious agriculture pest and are considered nuisance pests in human homes.
Bur chervil (Bur parsley) is an herbaceous plant with fern-like leaves and small white flowers. It can be found in most growing conditions, particularly in moist areas such as ditches and fields. Bur chervil easily out-grows native vegetation. Each flower produces two bur-like seeds that have a pronounced peak and are covered in bristles that easily stick to humans and animals to spread.
Butterfly bush (Summer lilac, Orange eye) is a semi-evergreen shrub that grows up to 5 m tall with a long, showy spike of tiny, purple flowers. This attractive, fast-growing plant has escaped gardens and now rapidly spreads into disturbed, open areas and along coastal forest edges, roadsides, and especially on sunny stream edges and riverbanks where it replaces native plants. Butterflies are often attracted to its flowers.
Canada thistle (Creeping thistle, California thistle, Cursed thistle) is a shiny green, spiny herbaceous plant of variable height with purple flowers. Plants form thick infestations through creeping rhizomatous roots that crowd out forage grasses in pastures and rangelands, reducing crop yields and production. Canada thistle is commonly found growing on roadsides, cultivated fields, pastures, logged forests, riverbanks, and other disturbed areas where it also out-grows native species.
Cheatgrass (Downy brome, Drooping brome) is an annual grass introduced to North America in the late 1800’s with hairy leaves and drooping spikelets. It can be found alongside roads or disturbed areas, or in sagebrush ecosystems where it can form dense stands and outcompete native grasses. It can dramatically alter wildfire regimes, as well as injure livestock and animals’ eyes and mouths by its sharp awns.
Chinese mystery snail (Black snail, Trapdoor snail) is the largest freshwater aquatic snail in BC with a large, distinctive cone-shaped shell. They were introduced to California in the late 1800s and have since spread to water bodies around North America. In areas where it is an established invasive species, it out-competes native freshwater snails and can reproduce to very high densities.
Common bugloss (Alkanet) is a hairy, biennial plant of variable height with small, purple flowers. It invades disturbed, sunny areas such as roadsides, pastures, and hay fields, which reduces the yield of these crops. It spreads primarily through seed, but root fragments can propagate. Bugloss leaves include alkaloid compounds which are toxic if ingested by humans or livestock.
Common burdock (Lesser burdock, Louse-bur, Wild rhubarb) is a biennial plant that forms a basal rosette with large leaves it’s first year and a very tall flowering stem it’s second year. It’s known for its clinging burrs that attach and cling to wild and farm animals. This can cause health issues such as blindness to these animals and allows burdock to spread large distances from a single plant.
Common comfrey is a fuzzy, herbaceous, perennial plant with white or purple flowers that grows to a height of 1 m. It primarily reproduces vegetatively and is notoriously difficult to remove due to its tendency to sprout whole plants from small root fragments. Its large taproot allows it to bioaccumulate nutrients in the soil and outcompete native plants.
Common periwinkle (Lesser periwinkle, Dwarf periwinkle) is a shiny evergreen trailing plant with showy purple flowers. It was a common ornamental groundcover popular for its fast growth and dense coverage. However, it has since escaped captivity and spread rapidly through BC forest’s understories, choking out native plant species.
Common snapping turtles are invasive to BC. They are much larger than any other turtle species found in BC, and may displace native turtles from their habitat or outcompete them for food.
Common St. John’s-Wort is a perennial plant that with dark green, opposite leaves and bright yellow, 5 petalled, clustered flowers. It grows in dense patches which can crowd out natural plants and reduce the grasses that animals feed on. St. John’s wort spreads by lateral roots and can produce up to 100,000 seeds per plant.
Common tansy (Bitter buttons, Cow bitter) is an herbaceous plant of variable height with fern-like leaves and yellow, flat-topped round flowers. It’s often found growing in sunny, disturbed areas such as roadsides or pastures where it can displace native vegetation. Infestations in rangeland can be toxic to livestock, and it’s reported that dairy cattle consuming the leaves often have unpleasant tasting milk.
Cypress spurge (Graveyard weed) is a short herbaceous plant with numerous yellow cup like flowers on stalks. It was originally grown as an ornamental but has since escaped into the wild. It prefers sun and can be found growing in open, disturbed sites like meadows, pastures, and roadsides. This plant and its sap are extremely toxic to humans and animals.
Toxic to humans, livestock and wildlife when consumed, or when its sap contacts skin. The sap causes nausea, vomiting and diarrhea when eaten. It can cause blindness if it gets in people’s eyes and skin contact causes redness, swelling and blisters.
Daphne (Spurge-Laurel) is a rhododendron-like plant with shiny green leaves and light yellow-green flowers. It is an escaped horticultural plant that can rapidly take over a range of ecosystems. It is especially suited to take over forest understories where it can form dense monocultures and outcompete native vegetations. It’s sap is mildly toxic to humans and animals.
Diffuse knapweed (White knapweed, Tumble knapweed) is a short flowering plant with white flowers, slender stems and leaves. It is often found growing in open areas and well-drained soils where they establish in grasslands, open forests, and along roadsides. They choke out desirable forage for livestock and wildlife and increase soil erosion. Seeds can be spread by wind, livestock, and people.
Eastern cottontail rabbits are a small to medium sized grey-brown rabbit with tails that are brown on top and white underneath. They are considered a serious threat to sensitive Garry Oak habitats on Vancouver Island and are also known to feed on several at-risk plant species. They reproduce rapidly, capable of 3-4 litters during their lives, with up to 8 offspring per litter.
Eastern grey squirrels (Grey squirrels) are a medium-large squirrel with grey, black, or sometimes white coloured fur. They will outcompete native squirrel species and birds for habitat, and feed on bird eggs and nestlings. They pose a threat to sensitive Garry oak ecosystems.
English holly (European holly, Common holly) is a plant with dark green, spiny evergreen leaves and shiny red berries that can grow as a large tree, shrub, or creeping vine. It’s an extremely adaptable invasive species capable of growing in shade or sun. Its berries are preferred by birds, allowing it to spread in unpredictable patterns.
English ivy (European ivy, Common ivy) is a creeping evergreen vine that can grow as dense groundcover or while climbing up trees. It was commonly planted to provide quick cover for walls and buildings, and as ground cover in commercial landscape. It spreads throughout rainforest understories where it suppresses native biodiversity.
Eurasian collared doves are a medium sized bird with a distinct ring of black feathers at the base of the neck, which is open at the throat. They prefer to nest in landscapes where people live and food is readily available. They can be an agriculture pest as well as facilitate virus outbreaks.
Eurasian watermilfoil (Spiked watermilfoil) is an aquatic plant with long slender stems, and thin feathery leaves. It has likely been let loose from aquariums. It can quickly take over waterways, causing sluggish water that attracts mosquitos and reduces the recreational potential of the waterway such as swimming and boating.
European chafer beetle is a small, light brown beetle with white fluffy hair on the underside of their thorax. It was first introduced to BC in 2001, likely through infested turf. They are a nuisance pest to homeowners, as they infest lawns and attract predators such as crows, skunks, and raccoons that damage lawns as they dig for larvae.
European fire ants (Common red ant) are small red-brown ants with two small backwards-facing spines at the end of their thorax. When their nest is disturbed, ants may emerge, swarm and deliver irritating stings. If you encounter a European fire ant nest DO NOT attempt to remove it yourself. In rare cases, European fire ant bites have led to allergic reactions.
European green crabs (Green shore crab) are an invasive crab that can be mottled olive green to brown, with five distinct spines between the eye and outer edge of the shell. They are a highly invasive species in many parts of the world, including along the BC coast. They are known to outcompete native crabs for food and habitat and could pose a serious threat to many other marine species.
European rabbits are a small rabbit, descended from domesticated rabbits – they can have the same size variety, and fur that may be white, black, brown or a combination of colours. European rabbits are herbivores and compete with native species for food and habitat. They were brought by settlers and were kept as pets or farmed for their meat and fur.
European starlings (Common starling) are a medium sized bird with black glossy plumage, small light spots and a bright yellow beak. They compete with native birds for food and space and cause serious economic impacts and damage to the agriculture industry. They feed and travel in flocks, sometimes reaching groups of 10,000 birds or more.
European wall lizards (Common wall lizard) were introduced to Southern Vancouver Island in 1967 and have slowly been spreading. The lizards are thought to spread by hitchhiking on vehicles, shipments of produce and plants or released by people who keep them as pets.
European waterlily (European white waterlily) is an aquatic plant with floating glossy green ‘lily pads’ on the water’s surface and large white flowers. It can be found in slow-moving water such as in lakes and ponds. This plant creates a swimming and recreational hazard by overtaking aquatic environments and choking out native species.
Feral pigs (Wild boar, Wild swine) are large descendants of domestic pigs with coarse, dark hair and sometimes tusks. Feral pigs are large omnivores, and are known to threaten various species of amphibians, ground-nesting birds, crustaceans, small mammals, mollusks, and reptiles in the regions here they have become established. They are also a serious agricultural pest by their rooting behaviour of upturning the surface level of soil in search of food.
Field scabious is a short perennial plant with large violet to pink clover-like flowers. It can found growing along roadside or in pastures. It crowds out forage and pasture plants, reducing food availability for grazing animals. A single plant can produce up to 2,000 seeds, which makes this plant difficult to remove once established.
Flowering rush (Grass rush) is an aquatic perennial with green, grass-like foliage and pink almond-scented flowers. It can be difficult to identify as it resembles several native species but will quickly crowds out other plants. It can be found in freshwater marshes, lakes or streams and reproduces primarily through its rhizomes.
Foxglove (Purple foxglove) is a tall flowering plant mimicking a column of bell-shaped flowers. It’s an extremely abundant exotic species that has naturalized throughout the province, leading many to believe this plant is a BC native! Found growing along roadsides, waste areas, and forests, a single foxglove specimen can produce 5,000 seeds each season. Every part of this plant (including the seeds) is extremely poisonous.
Fragrant waterlily (American white waterlily, Beaver root) is an aquatic perennial plant with round glossy green leaves that float on the water’s surface. This popular, fragrant aquatic perennial is still sold in garden and pond centers throughout the province despite its potential to invade and destroy our sensitive aquatic ecosystems.
Garden snails (European brown garden snail) are one of the larger snails present in British Columbia reaching 3.5 cm wide, with 4-4.5 whorls and the last whorl before the shell opening being much larger than the rest. This snail eats a wide variety of ornamental and agricultural crops and will compete with native snail and slug species for food and habitat.
Garlic mustard is a biennial plant with triangular, toothed leaves and small white flowers. In can be found growing in disturbed ecosystems, or in forest understories as it is a shade-tolerant plant. It reproduces by seed only and is unpalatable for herbivore grazers.
Giant hogweed (Giant cow parsnip, Cartwheel flower) is an extremely toxic invasive plant that is unusually large with deeply incised and sharp toothed leaves. Its sap will cause burns, blisters and scars when touched by bare skin. It can be found in moist disturbed soils, or riparian areas such as streams. It can grow very quickly and dominate ravines and stream banks posing serious negative risks to human health and ecology.
Giant knotweed is the largest of the knotweed species found in BC, with leaves that can be 16-20 cm wide and 30 cm in length. Knotweeds are frequently found in riparian areas, derelict land, road and railway right of ways and gardens. They thrive in moist soil and full or partial sun. Knotweeds can spread by seed, root fragments, and stem fragments, making them very difficult to control.
Goldfish are an invasive fish species that can come in a variety of colours, growing usually 15-20 cm long but occasionally as large as 55cm. Goldfish have been introduced in BC several times, likely the result of released pets. Goldfish thrive in brackish streams, ponds, and lakes with aquatic vegetation. Their negative impacts contribute to habitat loss for native aquatic species.
Goldmoss stonecrop (Biting stonecrop) is a rapidly growing succulent that was popular for rock and xeriscape gardens and is also occasionally used as a green roof species for its ability to withstand extreme temperatures and drought. However, this species is quite aggressively growing and overtakes other plants, rapidly spreading by both seed and vegetatively. A single leaf can root and turn into a whole new plant.
Gorse (Furze, Whin) is a spiny, perennial evergreen shrub. A mature plant can disperse up to 18,000 seeds per plant, and their seeds are easily distributed by human, environmental, and animal transport. Gorse poses a fire hazard due to its volatile oils. It is considered a noxious weed throughout the province.
Green frogs are an invasive frog species that are 5-10 cm long, with large eardrums behind their eyes and a raised skin ridge from their eyes down their backs. They can outcompete native frogs for nesting habitat and food including endangered native frog species.
Hairy cat’s-ear (Common cat’s ear, False dandelion) is a short, yellow flowered perennial herbaceous plant that invades pastures, meadows, roadsides, riverbanks, lawns, and disturbed sites. This plant can grow in a wide range of conditions, but thrives the most in sunny, open areas. It displaces native plants and is a nuisance weed on lawns.
Himalayan balsam (Policeman’s helmet, Ornamental jewelweed) is a short herbaceous plant with hooded white, pink or purple flowers. This plant will take over areas with moist soils, including stream and riverbanks. It has seed pods that when ripe, can explode or shoot seeds up to 7 m from the plant.
Himalayan blackberry (Armenian blackberry) is a large, thorny plant that grows from thick canes with small white flowers and producing large, shiny blackberries. It easily invades disturbed sites, pastures, roadsides, streambanks, and forest edges where it can create dense thorny thickets and crowd out low-growing vegetation. These thickets can produce 7,000–13,000 seeds per square metre.
Note: Both BC Priority Invasive Species List and iNaturalist have scientific name of Persicaria wallichii. Noxious weed list uses Polygonum polystachyum.
Knotweeds were introduced to British Columbia for use in gardens and landscaping due to their rapid growth and attractive appearance There are now four species established in BC: Bohemian, Giant, Himalayan, and Japanese knotweed. Knotweeds grow aggressively and are very hard to kill.
Hoary alyssum (False hoary madwort, Hoary berteroa) is a flowering plant with clusters of small white flowers with deeply notched petals. It spreads quickly through a long season of seed production. Seeds are dispersed by vehicles, equipment, footwear, wildlife, and birds.
Hoary cress (Heart-podded hoary cress, White top) is a perennial plant with numerous small, white flowers with 4 petals each. It invades open, sunny areas such as hayfields, meadows, and roadsides. It spreads by roots and seeds and crowds out native vegetation. It is considered a noxious weed in parts of BC.
Hound’s tongue (Houndstooth, Dog’s tongue) is an invasive plant with large dog’s tongue shaped leaves and red-purple, coiled flowers. It grows on dry, well-drained sites. Each plant can produce 2,000 -4,000 barbed seeds a year that cling to clothing, livestock, and wildlife.
Italian wall lizards (Ruin lizard) are invasive to BC but are not yet established. They thrive in habitats that have been disturbed by human activity and may be found basking in the full sun on rocks, tree trunks, fences or brick walls. They may outcompete our native lizard for food and habitat.
Japanese beetles were first found in BC in July 2017 in downtown Vancouver. Adult Japanese beetles can feed on over 300 species of plants, including many species of agricultural and horticultural importance.
Knotweeds were introduced to British Columbia for use in gardens and landscaping due to their rapid growth and attractive appearance. There are now four species established in BC: Bohemian, Giant, Himalayan, and Japanese knotweed.
Largemouth bass (Widemouth bass, Bucketmouth) was introduced as a stock fish and can now be found throughout BC. This species has a serious potential to disrupt food webs when introduced to new habitats and has been identified as a potential threat to multiple aquatic species at risk in BC.
Leafy spurge (Green spurge) is a perennial plant with green-yellow flowers in a flat-topped umbrella shaped. It is a garden plant that has escaped into natural areas and can now be found on dry roadsides, fields, grasslands, open forests, and disturbed sites. It can spread rapidly by its large root system, growing 9 metres down into the soil.
Marsh plume thistle (Marsh thistle, European swamp thistle) is a biennial plant with purple flowers, and spiny, hairy leaves. It prefers moist to wet, naturally open or disturbed areas. Seeds are spread by wind, water, birds, vehicles, and equipment.
Mountain bluet (Perennial cornflower, Montane knapweed) is a perennial plant with large, bright blue, ray-like flowers and long, lance shaped leaves. It is an escaped garden plant that invades natural areas. This plant can self-seed, which makes it difficult to control.
Mute swans are a large white swan with bright orange bills, holding their neck in a “S” shape. They compete for food and habitat with native waterfowl and other wildlife and can drastically alter aquatic ecosystems.
Myrtle spurge (Donkey tail, Blue spurge) is a short, creeping escaped garden perennial with oval, spiraling blue green stems and yellow-green flowers. It likes dry, disturbed soils where it grows quickly and aggressively, releasing chemicals from its roots which stop other plants from growing near it.
New Zealand mudsnails are a tiny aquatic snail that are light to dark brown, with 5-6 whorls hat lean to the right. The New Zealand mudsnail can live in a variety of habitats and can disrupt the natural ecology by out-competing native aquatic snails and insects.
Northern giant hornets are the largest hornet in the world that are bright orange, with large jaws and black eyes. They typically nest in underground cavities, or above ground in tree stumps of forested areas. They are not established in BC, but if they do they may pose a serious threat to our beekeeping and commercial pollination industries, creating serious consequences for BC agriculture.
Northern pike are a large freshwater fish with a pointed head, spotted back and silver belly. They have been introduced in many regions as stock for sport fishing and are spreading into southern BC. Northern pike has been known to deplete prey species from waterways, pushing out local large fish and collapsing food webs.
Nutria (Copyu) are a small to medium sized semi-aquatic mammal, with brown fur, a thin and round tail and a white muzzle with white whiskers. Nutria can turn lush wetlands into open ponds, destroying important habitat for native species of wetland animals.
Orange hawkweed (Orange hawk bit, Fox-and-cubs) is a short flowering plant that can grow from 30–60 cm in height with bright orange-red flowers clustered on top. It can create dense mats that crowd out native plants. Hawkweeds spread quickly through above ground runners, horizontal roots, and seeds.
Oriental weatherfish (Pond loach, Weather loach, Dojo) is an eel-like freshwater fish with six whiskers around their mouth. They are a widespread invasive species in North American freshwater systems which feed on aquatic insects, and compete with native fish for food, habitat, and spawning sites.
Oxeye daisy (Dog daisy, Marguerite) is an herbaceous plant of variable height with typical white daisy-like flowers with a yellow centre and wavy leaves. It was first introduced to North America in seed mixes. It is still commonly sold in many store-bought wildflower mixes and remains popular among gardeners despite its negative impacts.
Scentless chamomile (Matricaria maritima) is a similar species; however its leaves are fern-like, and it has smaller flowerheads.
Purple deadnettle (Red deadnettle, Purple archangel) is a short herbaceous plant with small pink flowers, square stems and hairy leaves. It lives as an annual or biennial. A single plant can produce thousands of seeds which remain viable in the soil for several years. It can also spread via stem and root fragments.
Purple loosestrife (Spike loosestrife, Purple lythrum) is a perennial shrub-like plant with a showy spike of, purple-pink flowers and narrow, stalkless leaves. It spreads rapidly by seed and root fragments. The tiny seeds are dispersed by wind, mud, moving water, wildlife and humans.
Queen Annes’ lace (Wild carrot) is an herbaceous plant with an umbrella-shaped cluster of white flowers, hairy stem and finely dissected, hairy, fern like leaves. It is common to roadsides and other disturbed areas. This biennial plant persists in clay soils and can be a threat to recovering grasslands.
Red swamp crayfish (Louisiana crawfish, Mudbug) are an invasive cray fish, that is a dark red colour with small red bumps on its head, claws and mid-body segment. It is not yet present in BC, but would damage local ecosystems by feeding on aquatic plants and invertebrates, competing with native species for habitat, and could spread diseases to native crustaceans.
Red-eared sliders (Red-eared terrapin) are an invasive turtle with red patches just behind their eyes. Their introduction into BC is likely caused by many pet owners releasing these turtles into natural ecosystems. Red-eared sliders compete with native turtles for basking sites, food, and habitat and may carry diseases such as Salmonella bacteria.
Rosy red minnow (Fathead minnow) is a small fish with silver sides and bellies and an orange-red or pink back, tail and head. It appears occasionally in waterways around BC, likely after having been intentionally dumped by pet owners. These fish can readily breed in BC waterways and would likely compete with other small fish for food and habitat if they spread.
Rush skeletonweed (Gum succory, Devil’s grass, Nakedweed) is a perennial plant with numerous wiry, branched stems, extremely narrow leaves and small yellow flowers. It invades rangelands, roadsides and disturbed areas. It competes with other plants for soil moisture and nutrients.
Russian olive (Silver berry, Oleaster) is a short invasive tree with silver leaves, black bark and small, yellow flowers. It can survive in dry conditions, cold temperatures and poor soils. It drinks more water than most plants in dry soil settings, therefore it can outgrow and compete with native species.
Rusty crayfish have two rusty-red patches on their sides, large claws with black tips, and a helmet-like head. They are not yet present in BC. They are frequently transported to new areas by fishermen in bait buckets. They have a diverse diet and may easily outcompete native species for food and habitat.
Scentless chamomile (Scentless mayweed, Wild chamomile) is a plant of variable height with daisy-like flowers of white petals and yellow centres as well as thin, carrot like leaves. It can produce up to 1,000,000 seeds every year, and the seeds can survive in the soil for up to 15 years. It prefers moist soil conditions and can aggressively take over pastures, grasslands, and other agricultural areas.
Scotch broom (English broom) is a woody shrub with bright yellow flowers, and small three leaflet leaves. It easily invades sunny, disturbed sites such as rangelands, roadsides, and areas of recent logging. Scotch broom can increase the intensity of wildfires, obstruct sightlines along roads, and crowd out native plants that animals depend on.
Scotch thistle (Cotton thistle) is a biennial or perennial plant with grey-green, woolly, lobbed leaves and spiney stems. It reproduces through thousands of seeds that can survive in the soil for over 30 years. Seeds can spread with the wind, but also in hay and water, and by attaching to clothing or animal fur.
Smallflower touch-me-not (Small balsam) is a twiggy, branching, fine-textured annual species with pale yellow flowers and serrated, glossy leaves. It is often found growing in moist soils such as those around rivers, streams, and wetlands ecosystems. Although this species prefers moist soils, it is tolerant to a range of sun exposures, soil types, and climates, making it difficult to eradicate.
Smallmouth bass (Bronzeback, Brown bass) are a grey-green fish with dark vertical stripes and a white belly. They have been introduced into BC waterways as sport fish. They have been known to deplete waterways of smaller fish and are considered a serious threat to native animals, including juvenile salmon.
Spongy moth are a small to medium sized moth that can be white with a dark zig-zag pattern or brown. They have not established in BC but are widely spreading in the Eastern United States and Canada. In their invasive range, Spongy moths are known to defoliate entire trees by feeding in large numbers. If they were to establish in BC, they would likely cause significant economic damage to our forestry and tree nursery industries, as well as residential properties.
Spotted knapweed (Panicled knapweed) is a biennial, herbaceous plant with several small, purple flowers with long, thin petals branching from the stem. It is a prolific seed producer, with individual plants producing up to 140,000 seeds per square metre. Seeds and plant fragments make their way into hay and the undercarriages of vehicles, allowing for new infestations over great distances.
Spotted lanternfly is a small insect with colourful patterned wings and yellow stripes on the side of their abdomen. They are not yet present in BC. In areas where it has become invasive, it has caused widespread damage and is considered an extremely harmful pest. Adults fly between host plants and may land on vehicles which carry them to new areas.
Strawberry blossom weevil is a small black beetle, with a downwards curved snout that is 1/3 of their body length. This weevil is a recent arrival in BC and has a serious potential to disrupt the BC berry growing industry. Adults can be found on a wide variety of wild and cultivated berry species until temperatures drop in the fall.
Sulphur cinquefoil (Rough-fruited cinquefoil) is a long-lived perennial with a 5 petal, pale yellow flowers and a palm-like hairy leaf. It invades grasslands, dry open forests, and disturbed sites such as roadsides and rangelands. A single plant can produce up to 1,600 seeds, living up to 20 years as new shoots can emerge from the main root.
Tamarisk (salt cedar) is a shrub-like tree with light green, scale-like leaves and light pink flowers. Its other known common name of ‘salt cedar’ comes from its ability to release salt from its leaves, which prevents the growth of any native vegetation within its range.
Tansy ragwort (Common ragwort, Stinking willie, Staggerwort) is a biennial to short-lived perennial with dense clusters of bright yellow flowers and ruffled, dark green leaves. It grows in pasturelands and disturbed areas. Seeds are easily transported by wind, soils, human activity, and livestock.
Teasel (Wild teasel) is a biennial plant with spiny, cone-shaped seed heads, small pink flowers and long thin leaves. It prefers sunny locations and can grow in a range of wet to dry soils. Spreading through seed dispersal, it typically invades meadows, pastures, roadsides, and disturbed areas.
Tench are large freshwater fish with a dark orange iris, and a single pair of barbel whiskers at the edge of their mouth. They have spread to BC from Washington through the Columbia River. They pose a threat to many native aquatic species, competing for food and habitat.
Tree of heaven (Ailanthus, Varnish tree) is a deciduous tree that can reach 20-30m in height, with small white flowers and oval shaped leaflets. It became popular in BC with gardeners for its rapid growth and interesting foliage. It produces by seed and by division and can sprout nearly anywhere, making it very difficult to eradicate!
The Virginia opossum (North American opossum) is a small to medium sized marsupial with mottled gray fur, white head with a pointed snout and pink nose. The priority for this species is to prevent its spread to new areas in BC, where it could potentially have unforeseen effects on native ecosystems.
Wild caraway (Meridian fennel, Persian cumin) is an herbaceous plant of variable height with fern-like leaves and white groups of lowers. It was introduced to Canada as a spice crop but has escaped cultivation. It is a biennial plant that can quickly outgrow native plants. It can grow in light shade, survive light frost and extra moisture in the soil.
Wild chervil (Cow parsley, Wild beaked parsley) is a biennial to short-lived perennial with small white flowers in umbrella like clusters and fern like leaves. It is typically found along roadsides, fence lines, streambanks, in ditches and competing with pasture and hay crops. It has a thick taproot that spreads aggressively, as deep as 2 m into the soil, and is very difficult to remove.
Winter moths are a variable moth species with fringes of hair at the base of their wings, being tan to mottled grey in colour. They are considered a threat to sensitive Gary Oak ecosystems and are occasional pests in cranberry bogs. They will feed on leaves and buds from a variety of tree and shrub species.
Yellow archangel (Artillery plant, Aluminium plant, Yellow weasel-snout) is a perennial plant with small yellow flowers on the leaf axils, and opposite hairy, round-toothed leaves. This plant prefers shady sites such as forested areas and grows in a dense mat that smothers other native plants. It spreads by seed and plant fragments, and by animals and humans passing through the vegetation.
Yellow flag iris (Water flag) is a perennial aquatic plant with bright yellow flowers on tall, smooth stems. It invades ditches, wetlands, streams, lake shorelines, and shallow ponds. This plant reproduces through seed dispersal and horizontal roots, and each rhizome fragment can sprout into a new plant, making it a difficult invasive species to control.
Yellow floating heart (Water fringe, Fringed water lily, Entire marshwort) is an aquatic perennial that resembles a water lily with its round, glossy leaves that float on the water’s surface and yellow flowers attached to sturdy, upright stems. It will form thick mats of vegetation in a sensitive aquatic ecosystem. It spreads both by seed and vegetatively, making this species extremely difficult to control.
Yellow loosestrife is a tall, fast-spreading perennial plant with yellow flowers. It prefers to grow in wet soils and is typically found in wetlands, wet roadsides, ditches, and along shorelines. It can form dense clumps that spread out over large areas, crowding out native plants.
Yellow perch (American perch, Striped perch) are an olive-brown fish with 7 thick dark stripes and a silver belly. They were intentionally introduced in BC as stock fish and from aquariums and private ponds, as well as accidental spread by boats and in bait buckets. Yellow perch reproduce quickly and may overwhelm and outcompete native predatory fish for food and habitat.
Yellow toadflax (Common toadflax, Butter-and-eggs) is a creeping plant with light yellow flowers and long, slim green leaves. It is typically found in cultivated fields, pastures, along roadsides and other disturbed areas. Yellow toadflax can out-compete native plants, which negatively affects plant crops, and reduces grass growing in pastures and rangelands.
Zebra and Quagga mussels are small freshwater mussels that grow to 3.5-4 cm with a distinct D shape and dark banding along the outside of their shells. They have not yet been detected in BC and are primarily spread in North America by recreational boaters. They can reproduce rapidly when invading new areas, damaging infrastructure and degrading recreational beach areas.