Fall Out of Love With Invasives

Fall marks the season of change, the days become shorter and most of our greenery begins to disappear. While a lot of our favourite plants begin to wilt, some species are just beginning the hard work to ensure their survival in the next year. Unfortunately for Ontario’s biodiversity, many of these plants are dreaded unwanted invasives.

What’s the big deal?

Invasive plants compete with our native species, often creating dense monocultures. Varying plant species that have co-existed in a certain area for often hundreds of years are now pushed out by these competitive, generalist, fast reproducing plants with little to no native enemies.

This is the problem.

Many species of plant set seed towards the end of the growing season, invasive species are no different. In this post we’re going to cover some of the lesser talked about invasive species to watch for this fall.

Norway Maple (Acer platanoides)

(Photo source: Credit Valley Conservation)
(Photo Source: Haliburton Master Gardener)

Our first species is Norway Maple, often rightly nicknamed the “tree killer.” This tree is often planted as an ornamental as it’s foliage typically stays on much longer, often late into the fall, much longer than that of our native maples.  The colour can range along the spectrum from green to yellow. This species is extremely invasive in North America. The Norway Maple grows in dense stands, which shades out our native sapling trees and wildflowers and competes for resources. As if that wasn’t enough to deter one from planting this invasive, it also releases toxins that alter the fungi and microbes in the soil. A few extra weeks of fall colours definitely do not out weight the negative of this species, always opt for native maple species in Ontario, and don’t plant the infamous Norway Maple.


Oriental bittersweet vine (Celastrus orbiculatus)

(Photo Source: BYGL, Ohio State University)
(Photo Source: University of Maryland Extension)

This lesser known perennial invasive vine is native to Eastern Asia, and can be found across several parts of Ontario. This vine forms a dense monoculture and pushes out native biodiversity and chokes out trees. Make sure not to confuse this vine with the native American bittersweet. A quick way to tell the difference between the two: on the invasive Oriental Bittersweet the berries grow along the vine with a yellow capsules, whereas the native variety has berries at the tip of the vine and orange capsules. These yellow capsules will burst open in the fall, making them a key ID factor this time of year. Oriental bittersweet has a competitive advantage against its native rival, it’s colour throughout the seasons is more attractive to birds, as well its berries tend to be more appealing. Not to mention the invasive variety, like most invasive species, is just generally better at reproducing.


Himalayan Balsam (Impatiens glandulifera)

Himalayan Balsam is not one of the lesser known species, unfortunately. This prolific invasive herb is extremely common and extremely invasive in Ontario. Native to the western Himalayas, some of the tallest reported sightings of this invasive species in Ontario have been found in Northern Ontario (over 8 ft!). This species made our fall list because of its unique method of seed dispersal, which occurs late in the growing season, towards the beginning of fall. This plant is accurately nicknamed the “Touch Me Not” plant, as the mature seeds will explode when disturbed, spreading as far as 5 meters away from the host. Because of this, humans often inadvertently help this plant spread further by brushing up against it, or tracking the seeds further along trails, back to their homes, etc. When developing a management plan, always avoid executing control efforts at the end of the growing season to avoid further spread.


Common Buckthorn (Rhamnus cathartica)

Common buckthorn, also known as European buckthorn is an invasive shrub, native to Eurasia. Often planted as an ornamental as it is usually the first to leaf out in the spring, and the last to lose its leaves in the fall. Under the Ontario Weed Control Act this plant is classified as a noxious weed, as it can alter the nitrogen levels in the soil to favour its own preferences. This can impede agricultural crop growth, thus leading to its classification as a noxious weed. If that wasn’t enough of an advantage, it is also able to germinate quickly and disperse its seeds over extremely long distances, allowing it to completely invade the under story of a forest. It is also often the overwinter host of a specific type of aphid that can destroy soybean crops. So how do you identify it in the fall? It produces clusters of berry-like black seeds in the fall. Avoid planting this species, and always opt for the native variety (Alder-leaved buckthorn).


So what now?

Invasive plants are often hardier than our native species, appearing earlier in the spring and lasting well into the fall. This is likely where the appeal to plant as an ornamental comes from, prettier for longer, and more bang for your buck. But buyer beware, these species will do a lot more harm than good in the long run.

Understanding the lifecycle of an invasive plant that spreads by seed is an integral part of any management plan. Planning a removal when the seed has set can lead to more harm than good. Always avoid planning a removal strategy around the plants seed dispersal timeframe, or plan to take extra precautions. Each plant will be different.

Seeds of invasive plants are also notorious for hitch-hiking on hikers and pets. To avoid being a vector for spread yourself use a boot brush and wipe away any visible mud and dirt from your clothing, pets and equipment.

If you think you’ve spotted an invasive species report it to eddmaps.org/Ontario or download the app on Android or iPhone. EDDMapS Ontario (Early Detection and Distribution Mapping System) is a real-time reporting application to track invasive species distribution in Ontario.

3rd Annual Garlic Mustard Pull Wraps Up in the Sault

The 3rd Annual Garlic Mustard Pull in Sutton Park in Sault Ste. Marie was held on May 26th. Over 25 volunteers came out to help remove this invasive weed. As well, for the second year the Scouts Canada Sault Ste. Marie Troop came out to lend a hand at their own pull following the main event. Sutton Park hosts the largest known patch of garlic mustard in Sault Ste. Marie. The event is funded by the Ontario Trillium Foundation, the EDRR Network partners with the Sault Naturalists, Sault Ste. Marie Region Conservation Authority, and Sault College. This year we removed 42 bags from the area!

One day a year, in the early growing season, we enlist invasive species warriors to come out and learn about the impacts of garlic mustard, while lending a hand in the removal of the plant. The control of garlic mustard, like most invasive plants, requires a multi-year management plan. The first goal of any management plan is just that; management! Our goal is to keep the established area in check, and control the further spread of the infestation. Monitoring of the site, conducted by Sault College and the Sault Naturalists, shows that the pull is keeping the established areas from expanding, with no, or relatively minimal new populations outside the managed area. This is great news! But the work is far from done, subsequent years of the management plan will be to continue diminishing the seed bank, which can last up to 7 years in the soil.

So why pull?

By removing the second year plants, you are reducing the number of seeds that drop into the seed bank. By removing the basal rosettes you are stopping those first year plants from making it to their second year, thus not allowing them to develop seeds that would drop down into the seed bank as well.

Thinking of hosting your own garlic mustard pull? Here’s what you’ll need:

  • Black, construction grade garbage bags
  • Gloves
  • Trailer or truck bed (to carry the bags away)
  • and somewhere to sun the bags, (in the trailer, on a driveway or other hard surface)

Tips for a successful Garlic Mustard Pull:

  • When working on public land, always check to see if a permit is required
  • Use construction grade bags to avoid tears
  • Don’t remove the material once in the bag, you run the risk of spreading infestation into new areas
  • Always leave plants in direct sunlight for one week minimum to kill all viable material
  • Pull the plant out as close to the ground as possible, ensuring you get the entire “S” shaped tap root
  • End of May to early June are great times to pull

Citizens Ready for Garden Season After Training Workshop

Saultites are ready for summer now that they have been trained to identify and report aquatic and terrestrial invasive plants at the Algoma Invasive Plant Workshop on April 22nd, 2018.

The free event hosted by the Early Detection and Rapid Response Network Ontario welcomed 32 people and focused on identifying invasive terrestrial and aquatic plants in the Algoma region. Participants had the opportunity to learn about what species are a risk to the Algoma area, what invasive plants are already here, and how to identify and report them.

Reporting an invasive species is as important as being able to identify them. Early Detection and Distribution Mapping Systems, or EDDMaps, is a tool that citizens can download on their phones or computers to report a sighting and can help prevent the spread of invasive species.

If you missed out on this workshop, what are some of the invasive garden species should you watch out for?

  • Periwinkle (Vinca minor)
  • Goutweed (Aegopodium podagraria)
  • English Ivy (Hedera helix)
  • Ox Eyed Daisies (Chrysanthemum leucanthemum)
  • Himalayan Balsam (Impatiens glandifulera)
  • Garlic Mustard (Alliaria petiolata)
  • Water Soilder (Stratoides aloides)
  • Water Hyacinth (Eichhornia crassipes)
    …and many more!

Taking on Garlic Mustard in Thunder Bay: Round 2!

Join us on Tuesday June 27th 2017 as we tackle Thunder Bay’s only known garlic mustard population with the help of our local volunteer network! During Thunder Bay’s 2nd ever garlic mustard pull we’ll show participants how to identify and remove this invasive plan. In following up on the great work completed by volunteers in June 2016 we’ll continue to ensure that this invasive plant doesn’t gain a foot hold in our community, as it has in many other parts of the province.

Free pizza and “How To” session begins at 6:00pm sharp! Pulling will begin at 6:30pm! Feel free to drop in at any time to lend a hand and learn about the impact of this invasive plant on urban biodiversity!

Please RSVP by email or phone with Colin at colin@oninvasives.ca or 705-748-6324 x281 to ensure we have enough food for everyone!

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Invasive Species Workshop for Ontario Teachers Announced – Saturday May 6th 2017

Join the EDRR Network and our friends at EcoSpark, Credit Valley Conservation Authority and the Riverwood Conservancy for a special workshop designed to help teachers bring invasive species content into their classroom. In this free workshop we’ll cover how to access a number of helpful education-oriented tools and resources designed to share knowledge on the 2nd leading threat to global biodiversity! Register for this event at www.ecospark.ca/terrestrial-invaders.

Terrestrial Invaders Workshop Poster

Invasive Species Summit – March 25th 2017

Invasive Species Summit for Emerging Environmental Professionals

March 25


WHAT:  The Summit is back! After a well-attended event in 2016, we’re delighted to host a follow-up workshop in 2017! This free, one-day, student led workshop will cover Ontario’s established and next wave invasive species. All taxa (plants, birds, fish, you name it!) will be covered. No prior expertise is needed to attend!

WHY:  Emerging researchers across Peel and Halton regions are contributing to exciting new research that is helping us better understand invasive species and their impacts on Ontario’s natural history. Student representatives from each of Peel and Halton region’s colleges and universities are invited to take part in this one day free workshop that has been sponsored by the EDRR Network of Ontario.

Participants will have the opportunity to network with peers from other institutions, studying similar issues, and share experiences gained from working on a range of invasive species found in Ontario.

Presentations will also focus on a range of invasive species that are not yet found in Ontario, and help introduce participants to the “Next-wave” of invasive plants, diseases, and other taxa.

WHO CAN PARTICIPATE:  Recent graduates living/working in the GTA, or any student  attending a local post-secondary institution such as:

·     McMaster University

·     University of Toronto

·     University of Guelph

·     University of Waterloo

·     Laurier University

·     Conestoga College

·     Mohawk College

·     Sheridan College

·     Humber College


Saturday March 25th 2017

9:30 am to 4:00 pm


Conference Centre

Sheridan College – Trafalgar Campus

1400 Trafalgar Road

Oakville, ON

L6H 2L1

COST: Absolutely free! We simply ask that you participate in the workshop, and ultimately help us broaden the “first line of defense” against new invasive species in Peel and Halton Region’s.

But that’s not all! We realize it can be a challenge for students to get to a meeting of this scale so to help alleviate any difficulties with getting to the meeting, we’re happy to be able to offer travel subsidies for any driver offering to carpool from their home campus, to the meeting. Connect with your institutional representative for more information.

REGISTRATION & MORE INFORMATION: For registration information please contact Colin at colin@oninvasives.ca.