GFM Network News


Perennial sow-thistle.

Perennial sow thistle costs farmers across Alberta

Noxious Weeds: Perennial sow thistle causes yield loss and acts as a host for pests

Often found in high densities across Alberta, perennial sow thistle seems to be a noxious weed that doesn’t quit. Not only does this pest cause significant yield loss in many crops, but it’s a host for several plant pests that attack economically important crops such as alfalfa, winter wheat and canola — just to name […] Read more

Devil’s trumpet — also known as jimsonweed, hell’s bells, loco-weed, and devil’s cucumber — is easily identified by either sight or smell.

Devil’s trumpet is a potentially deadly invader

Noxious Weeds: Jimsonweed

Although its exact origin is unknown, devil’s trumpet — otherwise known as jimsonweed — is found in many countries around the world in both agricultural and ornamental settings. Introduced to this province as a contaminant of agricultural seed, this smelly weed is under review by the provincial Agriculture Ministry and it has been recommended to […] Read more


Yellow clematis gets its name from its lemon-yellow nodding flowers.

Another invader from the buttercup family

Cultivation is not successful and no chemicals are registered for control

Yellow clematis, a perennial vine related to the buttercup family, can become quite invasive if proper precautions are not taken. In Alberta, it has been designated as noxious for this reason. Often purchased, however, from gardening stores as a bedding plant, this weed can spread by wind which can take the seeds far beyond the […] Read more




Seed from Canada thistle can germinate eight to 10 days after flowering, but roots — not seeds — are the main way that this noxious weed spreads.

This quick-spreading weed gets an early start

Noxious weeds: Canada thistle

Spring brings lovely native flowers, but also noxious weeds. The aggressive perennial Canada thistle is a favourite of disturbed soils of all types. It starts sending shoots from horizontal roots to the surface of soil around mid-April, with flowers to follow in mid-June and continuing throughout the summer. Easy to distinguish from other weeds, this […] Read more


The flower of field scabious is pretty but the weed can invade hayfields and other grassy areas and be widely dispersed via baled forage.

Don’t be fooled by this weed’s pretty flower

Noxious weeds: Field scabious

Field scabious was introduced as an ornamental from Europe and is now taking over roadsides and pastures. It can be found throughout central Alberta and has the ability to invade even undisturbed plant communities, such as hayfields. Once established it is very difficult to control. Flowers can be a purple- to blue-coloured clustered head, resembling […] Read more

Prevention through proper grazing management is the best way to keep absinthe wormwood out of pastures.

You won’t raise a glass to this invasive weed

Noxious Weeds: Absinthe wormwood

A tough, semi-woody perennial plant native to Europe and Asia, absinthe wormwood typically grows in stems and forms in a clumping habit. The most distinguishing feature of the plant is its finely divided leaves combined with a silvery-grey colour. Absinthe wormwood also has a very strong and distinct odour which is very similar to sage. […] Read more


Common buckthorn, which has been found in two Alberta locations, can easily outcompete native species.

This tree is also a noxious weed

Common buckthorn, otherwise known as European buckthorn, has been found in two locations in Alberta — in Edmonton along the North Saskatchewan River and in Stettler County. It was originally brought to North America from Eurasia as an ornamental, but soon spread throughout the continent. High seed production and excellent tolerance to Canada’s climate allow […] Read more

The barbs on the seed heads of Woolly Burdock allow them to easily attach to fur or clothing.

Noxious weed found throughout Alberta

Noxious Weeds: Wooly Burdock

Woolly burdock is found throughout Alberta and will grow in most soil types. It prefers moist, loamy, and well-drained soils which are in direct sunlight. This noxious weed is commonly found on disturbed sites, but has also been found growing in gardens for herbal use. Woolly burdock can only reproduce by seed, but is self-fertile […] Read more