Invasive Species

What are invasive species?

The Invasive Species Council of BC defines invasive species as "any non-native organism that cause economic or environmental harm and can spread quickly to new areas of BC". Alien invasive species are recognized globally as the second largest threat to biological diversity and native species.

What are invasive plants?

An invasive plant can be defined as "a plant that is non-native to the ecosystem under consideration and whose introduction causes, or is likely to cause, economic or environmental harm or harm to human health”. Many invasive plant species have no predators to keep their populations in check.
Click on INVASIVE SPECIES on the left sidebar for more detailed information.

List of Priority Invasive Plants:

Blueweed (Echium vulgare L.)

Biennial forb with numerous blue tube flowers on upperside of a short stem. Stems grow 30-80cm tall covered in short hairs. Leaves are also covered in hairs and are narrow (6-25cm

CANADA THISTLE (CIRSIUM ARVENSE)

Perennial forb with branched stem and spine-tipped leaves, growing to 2m in height. Bloom period is from June to October; flowers are purplish-pink, about 1cm in diameter, and in c

COMMON BURDOCK (ARCTIUM MINUS L.)

Common burdock is a large, leafy biennial that produces prickly burs. The leaves grow up to 50cm long and 30cm wide, are dark green above and hairy below. Purple flowers form in cl

COMMON TANSY (TANACETUM VULGARE L.)

An aromatic perennial forb with clusters of yellow flowers, growing to 1.5m in height. Bloom period is July to October. Flowers are button-like and yellow, in dense, flat-topped cl

DALMATIAN TOADFLAX (LINARIA DALMATICA)

Robust, branched perennial growing up to 1.2m tall. Each plant may have 1-25 flowering stems that bloom from May through September. Flowers are bright yellow with a long spur, rese

DIFFUSE KNAPWEED (CENTAUREA DIFFUSA LAM.)

Biennial or short-lived perennial in the Asteraceae (sunflower) family. The plant is 10-60cm tall with erect, branching stems with short, stiff hairs. Flowers appear from June - Se

HOARY ALYSSUM (BERTEROA INCANA (L.) DC)

An erect, branched plant growing to 1.1m. A cluster of small white flowers forms at the top of slender stems from June to September. Flowers are 4-6mm long with deeply notched peta

Hoary Cress (Cardaria draba (L.) Desv.)

Perennial forb in the Mustard Family. Grows up to 50cm tall with numerous white flowers with 4 petals giving it a flat-topped appearance. Leaves are alternate, 4-10cm long, blue-gr

HOUNDS-TONGUE (CYNOGLOSSUM OFFICINALE L.)

A taprooted, leafy plant growing to 1.2m tall. Blooms from June to September. Flowers are arranged in a line along upper stems and are small, reddish-purple, and have five petals.

Japanese Knotweed (Fallopia japonica)

Often called "Bamboo". Rhizomatous perennial with jointed stems growing to 3 m (10 ft) tall. Leaves are alternate on the stem, nearly heart-shaped, dark green on top and paler gree

Leafy Spurge (Euphorbia esula L.)

Designated Provincially Noxious, a perennial forb containing a white, milky latex. Mature plants are 20-90cm tall, smooth stems thickly clustered with yellowish-green small flowers

Orange Hawkweed (Hieracium aurantiacum)

Perennial forb containing milky juice. Orange to red ray flower with notched tips clustered at the top of a leafless stem. Stems are erect with stiff hairs approximately 1.3-1.2m t

PARASITIC DODDER (CUSCUTA SPP.)

A parasitic, annual forb with thread-like yellow to orange stems and no true leaves. The stems adhere to a host plant and coil around the foliage, sometimes forming dense mats. Suc

Sulphur Ciquefoil (Potentilla recta L.)

Perennial forb in the Rose Family. Light yellow (sulphur) flowers with 5 petals, 30-70cm tall on one to several stems growing from the rootstock. Leaves are alternate on the stem a

TANSY RAGWORT (SENECIO JACOBAEA L.)

Tansy ragwort is a biennial or short-lived perennial in the Asteraceae (sunflower) family. The taprooted plants have one or more branched stems, and grow to 1.2m in height. Flat-to

Yellow Flag Iris (Iris pseudacorus)

Perennial in the Iridaceae (iris) family. Grows up to 1.5m in height, with one or more showy yellow flowers per stem. Flowers are large, with three petals facing up, and three larg

YELLOW TOADFLAX (LINARIA VULGARIS)

Robust, branched perennial growing up to 60cm in height. Each plant may have 1-25 flowering stems that bloom from May through August. Flowers are bright yellow with a long spur, re