Protecting and enhancing the natural values of Salt Spring Island and its surrounding waters


Invasive Plants

>Invasive Plants
Invasive Plants2017-12-20T12:42:14+00:00

For photos and detailed information on individual species, scroll down.


The following plants are potential invaders or recent invaders. Their spread can be curtailed through vigilance.

Wild Chervil and Bur Chervil

Wild Chervil and Bur Chervil (Anthriscus spp) Wild chervil invades pastures and hayfields, reducing forage available for grazing animals and causes molding in hay crops. It can also be a host for a virus that attacks

Marsh Plume Thistle

Marsh Plume Thistle (Cirsium Palustre) Typically a tall, single, slender, unbranched stem covered in spiny wings with a cluster of purple flowers at the top. It can invade moist fields and meadows, replacing native vegetation

Himalayan Balsam

Himalayan Balsam (Impatiens glandulifera) Also known as Policeman’s Helmet, this plant is extremely invasive in moist, natural areas. It displaces native plants, but dies back in winter, leaving soils exposed and subject to erosion. FURTHER

Garlic Mustard

Garlic Mustard (Alliaria petiolata) This plant spreads quickly by seed, and displaces native species, especially woodland wildflowers, in deciduous and mixed forests. Classified as a noxious weed under the BC Weed Control Act. FURTHER INFORMATION

Clematis Vitalba

Old Man's Beard (Clematis vitalba) Also known as Old Man’s Beard, this fast-growing vine clambers up trees and forms a dense canopy, depriving other plants of sunlight. It grows in a wide variety of habitats,


Blueweed  (Echium vulgare) Blueweed invades meadows, pastures and rangelands, therefore infestations are associated with some economic losses. FURTHER INFORMATION

Dalmatian Toadflax

Dalmatian Toadflax (Linaria genistifolia spp. dalmatica) Classified as a noxious weed under the B. C. Weed Control Act, this snapdragon-like plant can form thickets that crowd out native species. Classified as a noxious weed under


Spurge (Euphorbia species)   A number of Euphorbia species are highly invasive, can chemically inhibit other vegetation, and can induce blisters in humans and animals. Leafy spurge, a designated Noxious Weed, has tiny yellow/green flowers

Yellow Flag Iris

Yellow Flag Iris (Iris pseudacorus) This attractive plant with three upward-pointing petals forms thickets in wetlands and severely reduces water flow, displacing native plants and damaging wildlife habitat.. Plant fragments may be spread and develop


Knotweed (Polygonum species) These large-leafed plants with tall bamboo-like stems and small white/green flowers can shade out native plants, especially near wetland areas. Classified as a noxious weed under the BC Weed Control Act. BC

Carpet Burweed

Carpet Burweed (Soliva sessilis) This hairy-stemmed low-growing (up to several centimeters) feathery plant with divided leaves carpets the ground and produces seeds with hazardous spines. On Salt Spring the infestation appears confined to Ruckle Park,

Purple Loosestrife

Purple Loosestrife (Lythrum salicaria)   This plant crowds out native vegetation, especially around wetlands. The purple flowers are set close along the stem (a “spike” arrangement) and usually each have six petals. The stem is

False Brome

False Brome (Brachypodium sylvaticum) This aggressive grass has flattened drooping flowers on very short stalks, and hairs on the leaf edges and stem.

Giant Hogweed

Giant Hogweed (Heracleum mantegazzianum) This tall plant shows spotted leaf stalks and purple/red colour on the stems. It shades and kills native vegetation, increasing risk of erosion. CAUTION: Touching the plant can result in a


At least 175 species of exotic plants have escaped into the forests of Salt Spring Island. Shown below are some examples of particularly aggressive plants that should be removed when encountered.


Common Tansy

Common Tansy (Tanacetum vulgare) Common tansy is a poisonous weed and is classified as a Noxious weed in BC. It is distinguished from Tansy Ragwort in that it has many yellow disc flowers. BC Invasives

Yellow Archangel

Yellow Archangel or Lamium (Lamium galeobdolon or Lamiastrum galeobdolon) This plant is often sold in hanging baskets or as a groundcover. It spreads aggressively in woodlands and riparian areas, climbing over and killing native plants


Periwinkle (Vinca minor and Vinca major) Both species of periwinkle grow rapidly and adapt to a variety of conditions, forming dense mats that suppress and out-compete other plants. Coastal ISC Species Profile

Butterfly Bush

Butterfly Bush (Buddleja davidii) Previously recommended for attracting butterflies, this bush is common on Salt Spring and is now considered invasive in southern BC. It spreads rapidly and displaces native vegetation in disturbed areas, forest

English Holly

English Holly (Ilex aquifolium) Holly is spread widely by birds, and adapts to a variety of habitats. It grows quickly and casts deep shade, depriving native plants of light, nutrients and water. Coastal ISC

English Ivy

English ivy (Hedera helix) Ivy is fast growing, shade-tolerant, and can climb and strangle native trees.

Spurge Laurel

Spurge laurel (Daphne laureola) The prickly canes of this plant may exceed 10 meters in length, creating dense thickets that shade out native plants. FURTHER INFORMATION

Himalayan Blackberry

Himalayan Blackberry (Rubus discolor) The prickly canes of this plant may exceed 10 meters in length, creating dense thickets that shade out native plants. BC Invasives Species Profile .fusion-tabs.fusion-tabs-4 .nav-tabs li a{border-top-color:#ffffff;background-color:#ffffff;}.fusion-tabs.fusion-tabs-4 .nav-tabs{background-color:#f4f4f4;}.fusion-tabs.fusion-tabs-4 .nav-tabs

Canada Thistle

Canada Thistle (Cirsium arvense) Canada thistle grows in sunny areas and can crowd out native grasses. Classified as a noxious weed under the BC Weed Control Act. LINKS: FURTHER INFORMATION  

Tansy Ragwort

Tansy ragwort (Senecio jacobeae) This plant with daisy-like flowers may exceed one meter in height. It can cause liver damage to animals that feed upon it. Classified as a noxious weed under the BC Weed


Gorse (Ulex europaeus) Gorse is a spiny shrub with yellow pea-like flowers. It can displace native plants and is a fire hazard due to its oil content. Classified as a noxious weed under the BC

Scotch Broom

Scotch Broom (Cytisus scoparius) This evergreen shrub with yellow pea-like flowers may cover sunny meadows choking out native vegetation and creating a fire hazard. LINKS: Broombusters