Invasive species are Medicine Hat’s most unwanted plants

By Gerry Ehlert on April 13, 2019.

Beauty and hardiness are important when selecting the plants we choose to grow. Unfortunately, some beautiful plants are too robust or harmful, and can invade our nearby natural areas.

On May 4, the Medicine Hat Interpretive Program and the Society of Grasslands Naturalists will host an Invasive Species workshop to help gardeners and landscapers make wise choices.

Experienced people will help to identify invasive species, and explain how we can work together to prevent their establishment and spread. Please let us know your interest by registering on http://www.eventbrite.ca or calling the Nature Line at 403-529-6225.

The Invasive Species qorkshop is sponsored by: Medicine Hat and District Horticulture Society, South East Alberta Watershed Alliance, Blondie’s Gift and Garden Centre, Animal World and Windmill Garden Centre. Additional sponsors are welcome – please contact us if interested.

Now let’s talk about the problems these species can cause and how we might address this on-going issue. Also, keep in mind, that invasive species are not just plants. There are numerous animals that are invasive, which will be addressed at the workshop as well.

Some popular garden and landscaping species, like creeping bellflower, Russian olive and European buckthorn, may soon spread beyond your yard. Once established, these problematic plants are difficult to eradicate, so one is faced with continued maintenance costs involving digging, pulling, and spraying. In addition, invasive species will likely out-compete other plants that you wish to grow.

Invasive species know no boundaries and can spread from an established site to other areas in our city, including adjacent properties, alleyways, vacant lots, and green spaces. Many invasive species like downy brome grass thrive with disturbance and continue to produce vast numbers of seeds. Invasive species love to “hitch a ride” using wind, water, animals, land and water vehicles, and human foot traffic to further establish themselves.

Unwanted plants, once they invade into a green space, particularly larger tracts of land such as native grasslands and parks, can be “there to stay and spread” despite continued efforts to control them. For example, Russian olive and yellow clematis are now established across southeastern Alberta in roadside ditches and along waterways. A recent invasive grass species that likely came from railways is reed cane grass (https://www.cbc.ca/news/canada/calgary/phragmites-australis-alberta-invasive-plant-wetlands-1.4531455).

Invasive species can be problematic and harmful to the environment, reducing wildlife habitat and populations and species diversity. Downy brome greatly increases the risk of grassfire, which helps perpetuate its presence (https://extension.colostate.edu/docs/pubs/natres/06310.pdf).

In 2004, the Alberta Research Council estimated there were about 50 invasive species in Alberta. By 2015, the number had grown to 279 species (https://abinvasives.ca). Many of these are found throughout Medicine Hat in a variety of areas. For example, European buckthorn, baby’s breath, salt cedar (Tamarisk) and purple loosestrife have all been reported. See the City of Medicine Hat’s website https://www.medicinehat.ca/government/departments/parks-and-recreation/pest-management/weeds .

Many invasive species have been here for years while others are new arrivals. Invasive species are specialists in “sneak attack.” For several years, they may go unnoticed and in some cases we even enjoy their beauty. Then, to the dismay of all of us and the environment, these plants suddenly show their true colours.

In 2004, the Alberta Research Council estimated that the environmental and economic costs of invasive species in Alberta are about $1 billion annually. Invasive species are very competitive and have many reproductive and vegetative survival mechanisms such as large seed production, strong annual growth, and roots that easily spread.

Knowing invasive species are unwanted, how can we screen against using these species in our properties or green spaces? In addition, if we find invasive species have established themselves, how can we cost effectively eradicate or control them? Many annual invasives leave their seed in the soil and this seed bank can serve as a continual source of germination and the production of more seed, establishment, and spread. This ongoing scenario continues despite our best efforts in digging, spraying and pulling.

There are often no silver bullet answers to these questions, and control will require time, increased awareness and education. We also need to know there have been success stories in our City with the prevention and control of invasive species. For example, early detection and control of purple loosestrife has kept it confined to a known and treatable area.

The Society of Grasslands Naturalists teamed up with Calfrac to greatly reduce baby’s breath in the Ranchlands area. Literally tens of thousands of plants were hand-dug over several years.

The horticulture industry has and is removing invasive species from their stores. The City of Medicine Hat, Cypress County and Alberta Environment have released biological control beetles along the South Saskatchewan River to control and reduce populations of leafy spurge. This will take time.

Awareness about invasive species is a first step. We need to be collectively informed about their presence, how to identify them, and what are the more successful biological, mechanical, and herbicide methods to consider. If we identify and find invasive species, we can report them so agencies are able to nip these most unwanted plants “in the bud.”

Other steps include team building, tool building, community action, and monitoring. Some valuable awareness and education information is provided by these organizations: Alberta Invasive Species Council; City of Medicine Hat; South East Alberta Watershed Alliance; MH Interpretive Program, Nature Centre, Police Point Park; Society of Grasslands Naturalists; Alberta Habitat Riparian Management Society (Cows and Fish); Canadian Council on Invasive Species; Alberta Environment and Parks

No matter how it gets done, these species need to be dealt with. Working together, we can have beautiful gardens and a healthy environment.