'Evil crab grass on steroids' moves into Alberta

Officials here say it's unclear how long Phragmites australis has been in the province, but they've pinpointed more than a dozen small stands within an area stretching from the southern grasslands to the Peace Region.

Phragmites australis can grow over five metres high and chokes out natural ecosystems

Crews work to get rid of a patch of Phragmites australis near Brooks, Alta. (County of Newell)

A towering invasive plant that has wreaked havoc in eastern Canada and the United States is now being tracked in Alberta.

Officials here say it's unclear how long Phragmites australis has been in the province, but they've pinpointed more than a dozen small stands within an area stretching from the southern grasslands to the Peace Region.

The reed, which grows in thick stands and can reach heights of over five metres, came to North America from Eurasia more than a century ago. In recent years, it's been called one of the country's worst invasive plants.

"If you want to picture it in terms of a prairie plant that we know, it's basically evil crab grass on steroids," said Calgary Zoo plant expert Boyd Nave. 

"It takes over large swaths of wetland. It literally drives out other plant species because it grows so incredibly densely."

'Horrible to get rid of'

Birds, mammals and fish are also affected as habitats are altered or destroyed by the plant, which has been designated a threat under the fisheries act.

Nave says controlling its spread has been a challenge out east, where the plant has thrived in wetlands from Nova Scotia to southern Ontario, using seeds and shoots to colonize an area.

"It is absolutely horrible to get rid of. It involves applying herbicide, which is kind of dodgy, because you're near watercourses often, then it requires either cutting or burning and then it comes up again next year and you kind of repeat," he said.

A towering invasive plant that has wreaked havoc in eastern Canada and the United States is now being tracked in Alberta. 0:38

"A very large stand, your best hope is to control its spread. You won't get rid of it."

Nicole Kimmel with Alberta Agriculture and Forestry says there are signs Phragmites australis is spreading west.

"We knew that it was likely to come here, we just didn't think it would be this soon. We are better served here in Alberta, if we can get on them when they're smaller rather than investing all that time when they get huge," she said. 

"Any users of the water basin in Alberta could be affected, and agriculture has a vested interest because of the irrigation infrastructure that it's closely associated with down in the south."

Two day fight

Kimmel says all of the sites discovered so far in Alberta have been contained. The first was detected in 2016 near Brooks.   

Todd Green is the director of agricultural services with the County of Newell, which encompasses the town. He says that site was one of three stands identified and contained in the municipality that year.

"What we found on the site specifically was about 13-feet tall and grew really thick ... in the thousands of plants in a very small patch," he said.  

"It replaced all the vegetation in this patch, native vegetation whether it be cattails, reeds or anything like that."

Green says it took a 12-person crew two days to cut and remove the plants by hand from that one small stand. All of it was trucked to a local landfill and buried.

He adds they also applied a herbicide the following year to prevent the plant from growing back. That step required special government approval because the herbicide was being used in a wetlands area.


Those tracking its spread believe the plant's seeds can hitchhike along transportation corridors including railways and highways, but they point out it also found a commercial route into the province. 

Before Phragmites australis was banned, it was once sold as an ornamental plant, along with other varieties of Phragmites, for lawns and ponds.

Officials believe two of the identified Alberta Phragmites australis sites were intentionally planted, including one at the Calgary Zoo.

Nave says the small stand was planted decades ago in one of the wildlife enclosures.  

Boyd Nave with the Calgary Zoo, says the invasive plant grows so densely it drives out natural vegetation. (Dave Gilson/CBC)

He says it only grows about five feet tall and hasn't spread. He believes the invasive plant doesn't thrive in Calgary because of the altitude and the colder climate.

Nave says the zoo will remove the stand this spring and says it illustrates the point that Albertans need to check their properties.

"It's still growing in peoples' gardens and it's just the idea we need awareness out there that this is a highly invasive plant, needs to be controlled. In fact it is illegal to grow it in your garden at this point."\

Native varieties

Officials say there is a native variety of Phragmites and stress it doesn't pose an ecological threat.

Kimmel says the province expects to find more sites containing the invasive version, and while officials continue to monitor wetlands and waterways, they're asking the public to keep an eye out as well.

"I think we've got a pretty good handle on the populations we've been able to find. They've all been quite small and isolated, so I think we've got a chance of continuing to keep it eradicated."

About the Author

Dave Gilson is a reporter at CBC News Calgary. You can tweet him @CBC_DAVE.