An invasive plant species is sinking its roots in Coldstream and some residents are taking notice and urging neighbours to educate themselves on the pesky noxious weed.
District of Coldstream chief administrative officer Trevor Seibel said the district has only recently been alerted to the issue of Garlic Mustard Seed and “are addressing as needed.”
“The District of Coldstream manages the noxious weed issue, on district-owned property, through a combination of spraying and hand removal,” Seibel said.
But the onus falls on homeowners to eradicate the horseradish-scented plant on private property.
Garlic Mustard, or Alliaria petiolata, can be seen around Coldstream Creek or Cosens Bay Road, residents said, but the aggressive biennial can harm the biodiversity.
Plants appear as a rosette of green leaves close to the ground, according to the Invasive Species Council of BC. They stay green all winter and develop flowers the following spring, growing from a long white taproot.
In its second year, the plant can grow from 30 to 100 centimetres. The leaves are stalked and triangular or heart-shaped. Leaves are 10-15 cm long, five to nine cm wide with a coarse, toothed margin, like a saw. Flowers are small and white with four petals arranged in a cross shape.
“Garlic Mustard forms dense monocultures that reduce the biodiversity and aesthetic value of natural areas,” reads a report by Ontario Invasive Plants.
The effects of the plant, which was introduced to North America as a food source and medicinal herb in the late 1800s, can be long-lasting or permanent as it releases chemicals that change soil chemistry, preventing the growth of other plants.
“It outcompetes and actively displaces native woodland plants, many of which are now listed as species at risk,” the document reads.
Garlic Mustard grows in a range of habitats and spreads quickly along trails, fences and roads. Seeds fall close to the parent plant and are picked up and spread by wind, water, wildlife, pets and humans.
Plus, it can self-pollinate, so only one plant is necessary to start a new population.
The Invasive Species Council of BC says the best way to prevent the spread of the self-pollinating plant is to brush off clothes, shoes and any recreational equipment prior to leaving areas infested with Garlic Mustard.
Lauren Bell, program manager with Ontario’s Invasive Species Centre said hand-pulling is very effective to get rid of the plant, but it must be done year over year to deplete the seed bank.
“Focus on second-year seed-producing plants and start your efforts on any outlying plants or outskirts patches in order to prevent further encroachment into natural areas,” Bell said in an email.
Best practices in Ontario include placing plants in black garbage bags — construction grade is recommended — and left in direct sunlight for at least one week before disposal.
The Regional District of North Okanagan accepts noxious weeds and invasive plants as controlled waste at its diversion and disposal facilities. There, bagged plants are buried in a timely matter preventing the risk of spread from handling and moving materials.