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Summary information on some invasive plants that are currently present in Port Moody is provided, with links to more detailed information.   

Canada Thistle (Cirsium arvense)
English Holly (Ilex aquifolium) 
English Ivy (Hedera helix) 
Giant Hogweed (Heracleum mantegazzianum) 
Himalayan Blackberry (Rubus discolor) 
Japanese Knotweed (Fallopia japonica) 
Orange Hawkweed (Hieracium aurantiacum) 
Policeman’s Helmet (Impatiens glandulifera)
Purple Loosestrife (Lythrum salicaria)
Reed Canary Grass (Phalaris arundinacea)
Saltmeadow Cordgrass (Spartina patens) 
Scotch Broom (Cytisus scoparius) 
Yellow Flag Iris (Iris pseudacorus)
Yellow Lamium (Lamium galeobdolon)

giant hogweed 

Canada Thistle (Cirsium arvense) 
Canada Thistle has small purple or white flowers in clusters of 1-5 at the branch tips. Leaves are long, narrow, and alternate on the stem with crinkled, deeply lobed, and spiny edges. At maturity, this plant grows to 0.3 to 2 m tall. It reproduces by seed but also spreads vegetatively through creeping, horizontal roots. Canada Thistle can be differentiated from all similar species by the lack of spines on the main stem, small flowers, and height (less than 2 m tall). Canada Thistle is classified as a Noxious Weed under Provincial legislation.

 

Canada Thistle (Cirsium arvense)
Photo courtesy: Invasive Species Council of BC 

English Holly (Ilex aquifolium)
English Holly is an evergreen tree with spiny dark green leaves and bright red berries. Flowers are whitish, sweetly scented and inconspicuous. Female trees produce berries in winter that are poisonous to people but not to birds. Birds contribute to the spread of this invasive. English Holly grows rapidly up to 7 to 10 m in height, and adapts to shady and sunny conditions. It often shades native plants depriving them of light. English Holly is also a high water user, and its roots can out-compete forest species for nutrients and water. Seedlings are now commonly found in mixed deciduous and coniferous forests around the south coast, along the edges of wetlands and especially near residential areas.

 

 English Holly (Ilex aquifolium)
Photo courtesy: Invasive Species Council of BC

English Ivy (Hedera helix) 
English Ivy, an introduced plant from Europe and Asia, is an evergreen vine with waxy leaves about 5 to 10 cm long. Ornamental plantings are the key cause for widespread introduction of English Ivy into forests and other natural areas. English Ivy grows all year and because it is well-adapted to the Pacific Northwest climate, it out-competes many other plant species. English Ivy can grow up to 20 to 30 m high and is usually found growing up tree trunks and covering the forest floor in closed-canopy forests around the Lower Mainland. When it grows up a tree, English Ivy can significantly degrade tree health and increase risk of trees being blown over. It can also cause aesthetic and structural damage to walls, fences and other infrastructure.

 

 English Ivy (Hedera helix)
Photo courtesy: D, Moore

Giant Hogweed (Heracleum mantegazzianum) 
Giant Hogweed (also known as Giant Cow Parsnip) has large umbrella-shaped white flowers and can grow up to 5 m in height at maturity. Giant Hogweed has dark green leaves that are coarsely toothed in 3 large segments with stiff underside hairs, and lower leaves can exceed 2.5 m in length. With prolific seed capacity, producing up to 100,000 seeds per plant, Giant Hogweed can spread quickly, dominating native vegetation.

If you come into contact with the sap of Giant Hogweed, remove any clothing that has come in contact with the plant. Wash skin thoroughly with soap and water and avoid exposure to sunlight for at least 48 hours. If you find Giant Hogweed on your property, special care should be taken for removal.

Giant Hogweed is classified as a Noxious Weed under Provincial legislation.  

 Giant Hogweed (Heracleum mantegazzianum)
Photo courtesy: B, Brown

Himalayan Blackberry (Rubus discolor)
Himalayan Blackberry is a European species of blackberry that was originally introduced for fruit production. It has become highly invasive and difficult to control. Himalayan Blackberry has small, white or faint pink flowers with 5 petals, arranged in clusters of 5 to 20. Canes grow up to 3 m in height and 12 m in length at maturity. Evergreen leaves are predominantly large, rounded or oblong. Himalayan Blackberry out-competes low growing native vegetation and prevents the establishment of shade-intolerant trees. This plant often takes over stream channels and stream banks through shading and build-up of leaf litter and dead stems.

 

 Himalayan Blackberry (Rubus discolor)
Photo courtesy: L. Scott

Japanese Knotweed (Fallopia japonica) 
Japanese Knotweed has small green-white flowers that grow in plumes off stem and lead joints. The stems are hollow and bamboo-like. Japanese Knotweed grows rapidly (up to 3 m per year) and spreads quickly, and can cause significant damage to properties and infrastructure. This plant takes persistence and diligence to control. It spreads through root and stem fragmentation – fragments as little as ½ inch can form new plants. If you find Japanese Knotweed on your property, special care should be taken for removal.

Japanese Knotweed is classified as a Noxious Weed under Provincial legislation.

Japanese Knotweed (Fallopia japonica)
Photo courtesy: J. Leekie 

Orange Hawkweed (Hieracium aurantiacum) 
Orange Hawkweed is a relatively new invader in the Metro Vancouver region. It has not been found in many places in Port Moody, but should be treated as quickly as possible so it is eradicated. Bright orange flowers and orange-red ray flowers sit on single, un-branched and leafless stem that is covered in black hairs. The plant is about 0.3 m tall. Orange Hawkweed can form a dense ground cover mat, out-competes native vegetation and provides no food value to wildlife.

 

Orange Hawkweed (Hieracium aurantiacum) 

Policeman’s Helmet (Impatiens glandulifera)
Policeman’s Helmet, also known as Himalayan Balsam, is a tall plant with pink, white and purple flowers. Policeman’s Helmet can grow up to 2 m in height and has hollow stems with long, slender leaves and flowers shaped like an English policeman’s helmet. It will grow tall and dense, displacing other plants and leaving bare soil prone to erosion when it dies back each fall, especially problematic in and around stream banks. Seeds are produced in tubular pods which, when mature, explode and can launch seeds up to 5 m away. Seedpods can split with little disturbance so significant care needs to be taken to remove the plant after it has flowered. When Policeman’s Helmet grows along watercourses, seeds can be propelled into the water and transported great distances. Seeds can be viable for 18 months or more.

 

 Policeman’s Helmet (Impatiens glandulifera
Photo courtesy: J, Leekie

Purple Loosestrife (Lythrum salicaria)
Purple Loosestrife is a woody half-shrub, semi-aquatic perennial with a stiff four-sided stem ending in dense spikes of purple flowers. Purple Loosestrife can out-compete most native species, yet provides little local food value, cover or nesting material. It invades wet areas at low-to-mid elevations, growing in ditches, irrigation canals, stream banks, lake and river shores, and tidal flats.

Purple Loosestrife is classified as a Noxious Weed under Provincial Legislation. Seeds remain dormant over winter and germinate the following spring or early summer or they can remain dormant for many years before sprouting. New plants can also sprout from root fragments.

 

 

 Purple Loosestrife (Lythrum salicaria)
Photo courtesy: L. Scott

Reed Canary Grass (Phalaris arundinacea) 
Reed canary grass is a cool season perennial grass species with noticeable creeping rhizomes. Cultivars introduced from Europe and Asia for ornamental use and pasture grass hybridize with native populations, producing aggressive offspring in the central and western regions of North America. This mixture of native and introduced types has resulted in debate about the invasiveness and origins of the species in some regions. It favours wet, poorly drained sites and may be found in ditches, along the edges of ponds and lakes, in marshlands, and in wet meadows.

 Reed Canary Grass (Phalaris arundinacea)
Photo courtesy: Invasive Species Council of BC

Saltmeadow Cordgrass (Spartina patens) 
Saltmeadow Cordgrass is an invasive foreshore grass that is spreading in Burrard Inlet and Port Moody Arm. Left uncontrolled, it can convert mudflats into monoculture grass stands, resulting in the loss of habitat for many species including migratory birds, shellfish, salmon, and other fish populations.

Saltmeadow Cordgrass is classified as a Noxious Weed under Provincial Legislation. Under the guidance of the Province, the removal of Spartina is being advanced by the BC Spartina Working Group (SWG). The BC SWG is a multi-agency collaborative of representatives from government and non-government organizations, and is developing a control plan for Spartina species in BC. The City is a member of this organization.

 Saltmeadow Cordgrass (Spartina patens)
Photo courtesy: BC Spartina Working Group

Scotch Broom (Cytisus scoparius)
Scotch Broom is an evergreen shrub with bright yellow, pea-like flowers that may have red markings in the middle. Scotch Broom grows to 1 to 3 m tall at maturity. It invades rangelands, replacing forage plants, and is a serious competitor to conifer seedlings. High density infestations of Scotch Broom can reduce wildlife habitat, hinder vegetation of wetlands and upland sites, and increase in wildfire fuel loads.

 Scotch Broom (Cytisus scoparius)
Photo courtesy: E, Coombs

Yellow Flag Iris (Iris pseudacorus) 
Yellow Flag Iris is not known to be widespread on City of Port Moody property, but should be treated as quickly as possible so it is eradicated. It is a clumping perennial herb that grows 40 cm to 1.5 m tall, and is the only totally yellow-flowered iris in BC. Yellow Flag Iris is most often found in fertile, low-lying wetland habitats (river banks, ponds, lakes, marshes), and can grow in both saltwater and freshwater. Yellow flag iris is particularly bad for cattails, sedges and rushes that are used by many birds for nesting. Plants need to be pulled or cut every year for several years to weaken and eventually kill the plant. Skin can be irritated by this plant, and gloves and appropriate clothing should be worn during disposal.

Yellow Flag Iris (Iris pseudacorus)
Photo courtesy: Invasive Species Council of BC 

Yellow Lamium (Lamium galeobdolon)
Lamium, also known as Yellow Archangel and Dead Nettle, is a trailing, evergreen, perennial groundcover with square stems and heart-shaped leaves. Leaves are typically variegated and slightly hairy. Lamium bears small soft-yellow flowers in mid-spring. It is a popular ornamental and is introduced into natural areas as intentional plantings or is dumped illegally as yard waste. Lamium is very aggressive and well adapted to growing in shaded and open areas. Seeds can be transported up to 70 m away from the parent plant. The plant also spreads by vegetative runners, smothering native plants.

 Yellow Lamium (Lamium galeobdolon)
Photo courtesy: J, Leekie
Last updated: 01/10/2015 9:52:01 AM