Invasive Plants

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Invasive Plants, Pacific Northwest

English Holly, BC Coastal Region, Invasive Plants
English Holly, Photo By Bud Logan

Invasive plant species are considered to be one of the greatest threats to biodiversity not just in the Pacific Northwest, but worldwide, second only to loss of habitat, the Pacific Northwest is being attacked by many invasive species of plants.

The Pacific Northwest has a very diverse ecosystem that supports many rare and endangered species that depend on these habitats for their survival, Invasive plants can take over and force the native plants out. The closer you come to communities, the more you see, spread by dumping garden debris in the forest. Some Plants like English Holly are mostly distributed by birds, the seeds will go right through them and then be delivered along with a good fertilizer. I have seen these trees a very long way from any road.

Scotch Broom, BC Coastal Region, Invasive Plants
Scotch Broom, Photo By Bud Logan

Invasive plants are brought to the Pacific Northwest, either accidentally or intentionally, and include species like purple loosestrife, scotch broom and japanese knotweed. These are just a few of the plant species that are threatening our indigenous plant species on our coast.

These invasive plants can get established easily and because they may have no natural predators, they can quickly take over an area and force out native species and this can also have an adverse effect on our native wildlife. As the animals usually do not eat the invasive plants and as these plants take over areas, it forces the wildlife to look further for food.

Some of these plants can have a direct negative effect on humans as well, some can have huge economic impacts by competing with agricultural plantings and forest harvesting areas. They can also pose significant threats to humans by causing skin irritation, burns and poisonings.

Purple Loosestrife, BC Coastal Region, Invasive Plants
Purple Loosestrife, Photo By Bud Logan

The Pacific Northwest has a real problem with these plants, everyone who lives here, especially on the coast, has seen the advance of plants like Scotch Broom. When I was a young man, you hardly ever saw this plant on the Island, now its everywhere you look. I was hiking up a mountain in the Kelsey Bay area this year and near the top, almost out of the tree line, there it was, scotch broom. Its everywhere.

The Cherry Laurel plant is native to southeastern Europe and Asia Minor. It has been introduced to North America and is used quite extensively as a garden/yard hedge. All parts of this plant is poisonous so care should be used in your choice of hedge material if you have children or pets that might induce this plant and its pretty looking berries.

Cherry Laurel, Pacific Northwest
Cherry Laurel, photo by Bud Logan

The Cherry Laurel can grow in a wide range of conditions. It prefers to grow under partial shade in well drained but moist soils, it can stand salt spray well and seems to thrive in acidic soil types. But it will grow in full sun or dryer soils almost as well. One cut stem can be the beginning of a tight growing plant that will take over the forest understory and crowd out other native plants.

It reproduces via seeds which are largely distributed by birds who eat the fruit. I have seen these plants growing a long way from the nearest road. But it can also grow new plants from trimmings and cut stems, so please avoid dumping this or any other invasive plant and instead, take it to a proper disposal site.

Cherry Laurel, Pacific Northwest
Cherry Laurel, photo by Bud Logan

Closer to most communities where this plant is used as an ornamental you will see many areas where it is getting a foot hold. As a Cherry Laurel plant gets established and begins to produce fruit, birds will distribute it further out and this makes this plant a problem invasive plant. Being such an easily spread plant, that is highly tolerant and very fast growing has led to this plant growing on most coastal areas of southern BC, it grows everywhere on Vancouver Island. Please think twice about growing this plant or for that matter, any invasive plant.

Giant knotweed is a tall shrub with bamboo like stems. It has been planted throughout south and central Vancouver Island and the Gulf Islands as a garden ornamental but has quickly spread to non garden areas to form dense thickets in a variety of habitats, including dry roadsides and moist stream banks. Small patches can quickly spread into large areas, leaving little room for native species to grow. It now can be found in most of the Pacific Northwest.

These plants can be identified by their tall bamboo like stem structure that can be up to 4 meters in height, leaves that are flat at the base with a pointed tip and small white flowers that bloom in late summer.

Giant Knotweed, Pacific Northwest
Giant Knotweed, photo by Bud Logan

I am seeing this plant growing up and down the logging roads surrounding the Campbell River area. I would have to surmise that most of these areas of intense growth of the giant knotweed are the result of home gardeners dumping garden and yard waste material that include the knotweed.

This is something that we should all be aware of and we should not dump debris that has the potential to redistribute invasive garden plants to the wild. Once these invasive plants get established, they are almost impossible to eradicate.

Please, think about this, invasive plants crowd out native plants and create a hazard that may be toxic to our native animals and birds.

Himalayan Balsam, Pacific Northwest
Himalayan Balsam, Photo By Bud Logan
Himalayan Balsam has flowers that resemble an english policeman’s helmet (one of its common names). It is native to the western Himalaya and was brought to Canada in the early 1900’s as an ornamental garden plant. This plant is swiftly spreading through the watercourses and along logging roads all over coast and is a real problem on Vancouver Island.

The plant does produce rhizomes. This plant also produces up to 2000 seeds from each plant. Himalayan balsam is shade tolerant. It is also quite common in private gardens where it often invades to such an extent that it becomes a real nuisance instead of a garden beauty.

Driving along the logging roads, you can see it growing along side the road where it looks quite pretty, but this plant is a real problem. It can grow to 3 meters tall and spread its seeds for up to 10 kilometers before they take root.

Himalayan Balsam, Pacific Northwest
Himalayan Balsam, photo by Bud Logan
Himalayan balsam primarily spreads its seeds by using waterways. So you have to go after the plant at its furthest upstream population first and then work down the stream thus stopping new populations from getting started. The plants that grow along the logging road must be pulled up and destroyed before their seed becomes mature.

Make sure to properly discard all plant pieces in thick plastic bags and transport them to a sanitary landfill site or incinerator. Do not compost.

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