Invasive Species Continue to Affect the Heath of the Credit River Watershed

An herbaceous plant with small white flowers dominating the forest floor.

Help Stop the Spread

Invasive species management and removal are critical to protecting the health and beauty of our watershed.  

The introduction of invasive species has had detrimental effects on the environment. Many invasive species were first brought here by settlers and continue to spread through many pathways. Their rapid reproduction and an absence of natural controls and predators make invasive species a serious threat to ecosystems. They displace native species and cause a decline in biodiversity.

There are 185 known invasive plant species in the Credit River Watershed, with new introductions found each year.

We can help stop the spread! Being aware of invasive plants, knowing how to spot them and taking action to remove them can help stop their spread and protect native species.

Invasive Species in Our Watershed

Discover essential facts about invasive species in the watershed and steps on how to remove them.

Garlic Mustard

A plant with triangular-shaped leaves with small white flowers, each with four petals.
Garlic mustard with flowers.
  • Garlic mustard, which people introduced as an edible herb, grows biennially and produces a lot of seeds
  • To prevent seed dispersal, pull out by hand before second year flowering plants drop their seeds in early summer

Common Buckthorn

A close-up of a shrub branch with leaves and purple berries.
Common buckthorn with seeds.
  • Common buckthorn is a European shrub common along hedgerows but it also invades a variety of natural areas
  • Birds eat its plentiful dark seeds which act as a laxative causing birds to expel undigested viable seeds acting as a vector for its spread
  • Remove smaller seedlings by hand pulling or extract saplings using a weed wrench

Non-native Honeysuckles

A shrub with oval-shaped leaves tapering at the end with yellow and white tubular flowers.
Non-native honeysuckles can look similar to some native honeysuckles, particularly when young.
  • Non-native honeysuckles, from the Lonicera genus, invade similarly to buckthorn
  • Often planted for its vibrant flowers, this shrub is a heavy seed producer, fast growing and easily out-competes native plants
  • Hand pull smaller seedlings or use a weed wrench to remove saplings


A close-up of plant with elliptic-shaped dark green leaves and purple flowers, each with five petals.
Periwinkle is a common invasive ground cover.
  • Periwinkle has long been popular as a low-maintenance ground cover
  • Its hardiness allows it to survive in gardens and enables it to establish in natural areas and prevents native forest growth
  • Hand pull and dig up its shallow roots

Asian Bittersweet

A close-up of a plant with yellow berries along its stem.
Asian bittersweet with plentiful berries along the stem.
  • Asian bittersweet vine is similar to its cousin, native bittersweet, but unlike the native kind it yields an abundance of berries along its stems
  • It aggressively climbs mature trees and wraps around them, potentially causing tree death
  • Hand pull smaller vines before they reach nearby trees or shrubs

Prevent the Spread of Invasive Species

Take a Handful

Managing invasive species can seem like a daunting task. With regular monitoring and removal of young plants, you can prevent invasive plants from establishing.

Hand pulling and digging up can effectively control small infestations of most species. Ensure that you remove the entire root system and always revisit the area to check for any regrowth. Remember to dispose of plant material in the garbage to avoid further spread.

Once species mature or become more established, a more comprehensive removal plan may be necessary. Our Invasive Species Management Team is available to answer your questions and connect you with more information and resources.

Help Set up Local Environments for Success

You can take action to help protect our local environment from invasive species:

Read CVC’s Invasive Species Strategy to learn more about how we’re responding to invasive species in the Credit River Watershed.


By Sarah Lebret, Associate, Marketing and Communications

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