What You Need to Know About Invasive Plant Species in BC

Japanese Knotweed (Polygonum cuspidatum)


What is an invasive plant species?
An invasive plant species is any species with the potential to pose undesirable or detrimental impacts on people, animals or ecosystems. Introduced from outside their native regions, invasive plant species are also commonly referred to as alien, non-native, exotic or introduced plant species.

What’s the problem with invasive plants?
Whether they arrive accidentally or intentionally, non-native plant species arrive without their natural predators and pathogens. Unchecked, they thrive in their new environments. Prolific seed production, deep taproots and early flowering enable these highly competitive species to establish quickly, posing a serious threat to native species, agricultural crops and forest plantations.

Where do invasive plant species come from?
Many species were introduced as far back as the 1800s by early settlers and explorers, and have since tenaciously spread their way across the continent. Others found their way into the landscape more recently as intentionally planted ornamental garden novelties.

Scotch broom (Cytisus scoparius) is perhaps the most obvious example of an invasive plant species here in BC. Yes, this escaped garden ornamental shrub adds a lovely splash of colour to many a coastal landscape—vibrant yellow as far as the eye can see. Unfortunately, this burst of colour brings with it a host of problems for native plant species, agriculture and forestry operations.

How do invasive plant species spread?

According to our friends at the  Coastal Invasive Plant Committee some of the most common vectors of spread are:

  • Contaminated seed, feed grain, hay, straw, mulch
  • Moving unclean equipment and vehicles across uncontaminated lands
  • Recreational and commercial boating
  • Livestock and wildlife
  • Spreading gravel, and road fill, that contains seed
  • Nursery industry, gardening and landscaping
  • Recreation (e.g. on the soles of hikers boots)
  • Water and wind transportation

Canada thistle (Cirsium arvense) is another noxious weed you’ll find on the CIPC’s list of “Species of Concern”. This root-creeping, stalkless, spiny perennial has dark-green leaves with purple or white flowers and can grow as tall as 2 meters.

What can you do about invasive plant species?

There’s a lot to know about invasive plant species. You can probably recognize the worst offenders in your area, but the fact is, CIPC estimates tens of thousands (egad!) of invasive plant species are sowing their wild seeds across coastal British Columbia.

The good news is: there are a number of resources, organizations and individuals committed to spreading the word, not the weeds! To learn more about identifying, managing, controlling and eradicating invasive species check out these handy links:

Purple loosestrife (Lythum salicaria) reached North America via early Eurasian explorers in the 1800s (making its way to British Columbia by 1915). Found in wet areas—ditches, irrigation canals, marshes, streams, lake shorelines, and wetlands—this showy, purple flowered perennial is known for it’s impressive seed production (3 million seeds per plant!).

Join us for the 7th Annual Coastal Invasive Plant Committee’s AGM, Forum and Hands-on Field Tour!

The CIPC’s theme for this year’s event is “Vectors of Spread”. You can expect a stimulating day of sharing and learning. Highlights include:

  • Networking with other stakeholders from Vancouver Island, the Gulf Islands and the Sunshine Coast
  • Engaging in cafe-style dialogue sessions with local experts
  • Participating in hands-on workshops, including a stem-injection demonstration
  • Learning how to control some of the worst invaders

PFLA is proud to be associated with the CIPC and we look forward to an informative and engaging event. Hope to see you there!

Where:  Mews Conference Centre, Royal Roads University (RRU)

When:   Thursday, June 7th, 2012 – 10 a.m. to 4 p.m.

Find schedule and registration details at CIPC’s online registration form.

Giant Hogweed (Heracleum mantegazzianum) Initially introduced from Asia as an interesting garden ornamental, they don’t call this alien plant species “giant” for nothing. A member of the Carrot or Parlsey Family, giant hogweed grows up to 6 meters tall! Photo courtesy of the French Creek Giant Hogweed Project.

If you can’t make the June 7th, CIPC event, worry not. We’ll also have an invasive plant species presentation as part of the Private Forestry Forum at the PFLA annual general meeting, June 20-21, 2012.

Spread the word, not the weeds!