If you want to see the front line of the weed war in St. Albert, go to the vacant lot by Meadowview Lane and Meadowview Drive.
This is weed central in St. Albert, says city arborist Kevin Veenstra as he wades into the lot's waist-high grass – a place where he easily spots about seven provincially-regulated weeds in less than 100 paces.
"That yellow-topped one there?" he says, indicating a green sprig with clusters of tiny yellow flowers. "That's leafy spurge."
There are maybe 100 or more of these plants here, each full of latex-like milk that can irritate skin and poison livestock.
"There's only three spots in town with leafy spurge, and this is by far the biggest."
There's scentless chamomile, known for its white daisies; the dandelion-like sow-thistle; the omnipresent Canada thistle; and burdock.
"If it wasn't for our crews picking, pulling or digging every burdock in this town … this town would be overrun by them," Veenstra says.
And this is just the edge of this huge field.
"The weeds here are some of the worst we have," Veenstra says.
Unchecked, these plants will roll into St. Albert and flatten our native plants and animals. Holding them back are a handful of scientists, field-men and volunteers – all of whom need the public's help if they are to stand a chance in the war on weeds.
Know your enemy
Linda Hall has spent the last 15 years wrangling weeds as a weed scientist at the University of Alberta, both in the lab and in her experimental plots at the St. Albert Research Station north of town.
"I spend a third of my time on my knees in the mud and the rest of the time I have to pretend I'm a professional," she quips.
A renowned weed researcher, Hall says her first experience with weeds came while hoeing sugar beets in southern Alberta. No matter how often she hoed them down, the weeds always sprang back up.
"We always think of plants as being very passive," Hall says, but weeds are not – they invade fields, survive harsh conditions and travel vast distances. They're promiscuous, persistent creatures – the kind of organism you'd like to meet at a cocktail party but wouldn't want to bring home.
"It's very interesting to study the bad boys of the plant world," she says.
Keeping an eye on those bad boys is Barry Gibbs, executive director of the Alberta Invasive Plants Council and member of the Alberta Weed Regulatory Advisory Committee – the group that decides what weeds the province regulates.
Weeds are more formally known as invasive plants, Gibbs says, which are prolific, often introduced plants that spread uncontrollably.
"They move in and they form dense monocultures."
There are about 21 different traits that make a plant a weed, Hall says, but the three key ones are abundant seed production, the ability to grow just about anywhere, and chemical warfare.
Take diffuse knapweed, for example. Hall and her team are growing a table-load of it in a secure greenhouse in Edmonton.
This unpalatable invasive plant produces scores of spiny purple flowers on the ends of thin green stems, she explains, each capable of producing thousands of seeds that are released when the plant dies and tumbles across the plains. The plants also leach chemicals into the dirt that stop anything but knapweed from growing in it – a trick that's helping it take over Alberta's native rangelands.
Such "dead zones" crowd out native plants and animals, Gibbs says, disrupting local ecosystems. The plants themselves can also threaten livestock, people and buildings (in the case of the concrete-cracking Japanese knotweed).
These plants aren't inherently bad, Hall notes – just too successful for our purposes.
"The definition of a weed is a plant you don't want," she says.
And in many cases they're our fault. Flowering rush, purple loosestrife and many other plants on the provincial weed list are ones that escaped gardens and ran amok due to a lack of natural predators. Others have spread due to contaminated seed, dirty combines, cars and boats.
Field tactics
Weed infestations are like fires, Hall says – easy to stop at first, but tougher the longer they go on.
Veenstra points out two raging infernos on the east side of St. Albert. The fields of purple, carnation-like blossoms now dancing near Kingswood Park are field scabious, and it's already engulfed most of Riverlot 56.
"We're talking acres and acres and acres" of it, he says.
Nearby in the river is an innocuous-looking bed of triangular reeds. This is the flowering rush, Veenstra says – the biggest weed problem in the city. Known for its big bunches of pink flowers, this escaped ornamental pond plant has grown so thick in American lakes that it's made many un-swimmable. It's spread down the Sturgeon from Kingswood to the Starkey Road bridge and shows no sign of slowing down.
Research can come up with new tools to stop these weeds. Hall's lab is working on new chemicals to thwart garlic mustard, while others are looking for predatory insects that eat weeds.
Some of the most effective controls are also the simplest, Hall notes. Many weeds can be hand-pulled, mowed, or tilled under. Others, such as leafy spurge, can be devoured by hungry sheep. Densely-planted, healthy crops and lawns can crowd out weeds altogether.
One of the most potent weapons against weeds may be people. Edmonton and St. Albert have both mustered volunteers for mass pulls of invasive plants in their parks.
The City of St. Albert has teamed up with Poundmaker's Lodge, Riverlot 56, Sturgeon County and the province to handle flowering rush and field scabious, Veenstra says, as the plants can be found in all their jurisdictions.
In addition to teaching each other about invasive plants, the groups are co-operating to track, map, and pull these weeds. They also plan to crowd out field scabious (a grassland species) by planting trees and shrubs on it.
One of the biggest challenges with weeds is that there are more weeds than weed experts to spot them, Gibbs says.
"The more eyes that are out there and recording stuff, the better."
A possible solution is EDDMapS – the Early Detection and Distribution Mapping System. Launched in Alberta last year, this U.S.-based website has smartphone users spot, photograph and report invasive plants in their region and post the results on an online map. Experts then confirm these reports and use them to find infestations.
The project is still in the pilot stage, Gibbs says, with just a handful of records for Alberta so far. Still, his group hopes it will eventually become an early warning system for weed outbreaks.
We've already "lost" the war with hundreds of weeds, Hall says, including dandelions, as they're too widespread to control.
"We've learned to live with a whole lot of alien invaders."
It's not so much winning the war as it is holding the line, Hall says.
"You don't have to have an expensive method of weed control, but you do have to be as persistent as the weeds are."
Individuals can help by researching what they plant in their gardens, cleaning cars and boats before they leave a site, and reporting weeds when they find them, said Gibbs. (He's also looking for volunteer spotters to bulk up the EDDMapS project.)
"The more we do, the better we'll preserve Alberta the way it was all along," he said.
Visit invasiveplants.ab.ca for more on how to spot weeds.
