They might look beautiful to the gardener’s eye, but orange hawkweed and red bartsia don’t have any friends in agriculture.
Orange hawkweed, also known as devil’s paintbrush, has officially made its way into Manitoba after sightings in the municipalities of Piney and Stuartburn.
The Tier 1 noxious weed is noted for its bright-orange to red blooms, single tall stalk and voracious spread. The western Prairie provinces, British Columbia and Ontario are all embroiled in a fight against the weed. A fact sheet put out by the province of Alberta notes that the weed commonly chokes out perennial grasslands with a mat of rosettes, while the weeds themselves can reproduce through seed, their tall stems or by rhizomes below the soil.
Why it matters: Farmers scouting their pastures might want to look out for these invasive species.
Tammy Jones, Manitoba Agriculture’s weed specialist, has also noted the plant’s voracity with concern. Seeds are already primed and ready when the plant flowers, she said during a weed seedling identification day in Brandon, and there are parts of Manitoba that already show wide patches of orange.
“Orange hawkweed is not something we’re going to manage overnight,” Jones said. “It is going to be a challenge to get through because it is in native prairies, ditches; there are some wildflowers there that are also important to people that we need to preserve.”
Jones likened it to the fight against diffuse knapweed, a noxious weed that has been an ongoing challenge in the Municipality of Stanley.
Unlike orange hawkweed, the fight against red bartsia is nothing new. The narrow-leafed plant with its spike of reddish-purple flowers has been a problem in the Interlake since the ’50s when it was introduced near Gimli.
The Invasive Species Council of Manitoba (ISCM) later reported it near Souris, Carman, Stonewall, Selkirk and parts of Winnipeg.
Jones has since also heard of red bartsia in the Municipality of La Broquerie and by Killarney. Jones suspects those cases are due to hay bales containing red bartsia seed.
Red bartsia is a Tier 1 noxious weed in every area of the province but the Interlake, where it is already widespread.
Tier 1 areas are eradication zones for the plant, while the province holds little hope of eliminating the species in the Interlake, downgrading it to Tier 2 in those regions and refocusing efforts on managing the population.
The plant can be an economic hit for pastures and hay land. The ISCM says the weed can outcompete forages, while Jones noted that the parasitic weed feeds off of surrounding plants, latching roots onto surrounding root systems and stealing nutrients.
The plant itself produces up to 1,400 seeds a year, which Jones says can persist for nine years and which are covered in hairs that can stick to clothing, fur and vehicles and spread the weed.
There are four municipalities in the Interlake that allocate a joint $170,000 annually to control red bartsia, Jones said.
“Those four RMs are working really hard to try and control it and just keep it in their area, whereas there’s these isolated plants in other areas that we should be able to destroy and never get to the point where it’s so widespread that we have to be spending that kind of money,” Jones said.