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Regional Weeds of Distinction

If left unmanaged, plant species designated under the Alberta Weed Control Regulations have the potential to devastate a variety of land uses. These designated plants can create monocultures by outcompeting our native species. This in turn affects cereal, oilseeds and forage crop yields; depletes soil quality; ruins infrastructure; and can be toxic to human and animal health.

It’s important that the MD and residents work cooperatively to ensure that these designated plant species are managed, by utilizing Best Managed Practices that directly affect our ecosystems.  

Prevention is the Best Form of Control

Employing simple techniques such as washing equipment (including ATVs/UTVs) between fields before and after use is an effective strategy. Also, interrupt weed seed analysis both in crop and garden/flower purchased seed and/or mixes, and become familiar with our area’s designated weeds and their Best Management Practices. Not every species is the same, and each may require a different method of control.

Is wica flower 01

Employing best management practices (BMP) can involve mechanical control such as mowing or hand-picking; biological control methods using insects, grazing and cover crops; or chemical control measures via herbicide use.

Applying a BMP that is best suited to the land use and targeted species will require constant monitoring for overall effectiveness.

Be sure to consult a reputable source about which herbicides and tank mixes will prove most effective, as some plants are known to be resistant to certain herbicides (e.g.: glyphosate [Round-up] and 2-4-D).

Often, applying an integrated management approach is the most effective and practical solution to a weed infestation.

Weed Management FAQ

What is the Alberta Weed Control Act?

Provincial legislation enabling Alberta municipalities to prevent the introduction and spread of provincial and/or municipal designated plant species that pose significant social, economic and/or ecological risk.

Who is held accountable under the Weed Control Act?

Any person, governing body, business or organization that owns or occupies land within Alberta.

As a landowner or occupant, what does the Alberta Weed Control Act mean to me?

If a designated plant species is growing on land that you own or occupy, you are required by law to control/ destroy the designated plant species.

What is the difference between Prohibited Noxious and Noxious Weeds?

Prohibited Noxious Weeds are to be destroyed (kill all growing parts or render incapable of reproduction).

Noxious Weeds are to be controlled (not capable of spreading).

How do weed species spread?

Weeds can spread numerous ways, both natural and human assisted by airborne and physical movement of seeds, roots, plant parts and contaminated soils.

Can a weed inspector enter my property without permission?

Yes. The weed ispector is allowed on private property without permission as sanctioned by the Weed Control Act at a reasonable time. An Inspector is only allowed on private property to monitor or enforce a notice within compliance of the Act. The inspector must have appropriate identification and present it upon request.

Can a weed inspector enter any building on my property?

No. A weed inspector can only enter a private building if the owner or occupant of the building provides consent or by written permission.

I don't want my property inspected. Can I tell the Inspector to leave?

No. A person shall not willfully obstruct or delay an inspector in the exercise of the inspector’s duties or powers to enforce and monitor in compliance with the Weed Control Act.

What happens if an inspector finds designated weeds on my property?

Under normal circumstances the inspector will try to contact the occupant and/or the landowner to discuss control methods and the severity of the infestation. If contact failure is unsuccessful or in the event of an absentee landowner a notice may be issued to the affected parties. The notice will contain the following:

  • legal land location
  • approximate location of the weed(s)
  • registered owner
  • type of weed(s) found
  • method of control recommended
  • time frame for the method to be completed
  • name of the inspector
  • the appeal process if the landowner wishes to contest the conditions of the notice
What if the conditions of the notice are not met?

The MD has the authority to enforce the notice (conduct the said control methods) and all costs associated inclusive of administration costs will be billed back to the landowner per the Weed Control Act and MD policy. Failure to pay invoiced costs will result in these costs being placed on the landowner’s property taxes.

What if I want to contest an enforcement order and its associated costs?

The MD has as an independent agricultural acts appeal panel that may hear all agricultural act appeals and review all  agricultural appeal requests. In order to action this process, all conditions of the appeal process need to be followed and can be obtained by contacting the MD’s Chief Administrative Officer.

Gallery canada thistle 01

Canada Thistle — Cirsium Arvense

NOXIOUS: Canada Thistle is an aggressive perennial that can spread by creeping roots and by seed. Canada Thistle can grow in a variety of soils but thrives in disturbed areas and overgrazed pasture/rangelands. Its flower heads are urn-shaped, vary in colour being purple, pink or white and the bracts are spineless.

The leaves are lance-shaped, dark green in colour, grow alternately on the stem and the edges can vary from smooth with no spines to irregularly lobed with sharp spines.

Canada Thistle is the only thistle, native or introduced, with separate male and female plants.

Gallery canada thistle 02

Mechanical BMP: Control of the root system is the only effective method. A combination of cutting and herbicide application during active growth periods (early spring and late fall) is best. Sheep and goats will readily graze rosettes before plants reach the spiny stage.

Weeds are Not Forage

Invasive species should not be considered forage unless no other control method can be used. Mowing & hand picking will gradually deplete the energy reserves in the root systems.

Chemical BMP: Herbicides such as 2, 4-D, Aminopyralid, Chlorsulfuron, Clopyralid, Dicamba, Glyphosate Hexazinonem Metsulfuron-methyl, MCPA and Picloram are registered for use.

Gallery common tansy 01

Common Tansy — Tanacetum Vulgare

NOXIOUS: Common Tansy is a perennial forb that thrives in disturbed areas and well drained soils. Identifiable by its bright yellow button-like flowers, and deeply divided into numerous narrow, individual leaflets with toothed edges.

This plant has rhizomatous roots and can re-grow from severed root fragments. Common Tansy contains alkaloids that are toxic to both humans and livestock if consumed in large quantities.

Gallery common tansy 02

Mechanical BMP: Cultivation of this plant will result in flowering stems and re-growth. Regular mowing can reduce seed production but must be repeated to eliminate regrowth from the root stalk. A combination of mowing/hand cutting with herbicide control and encouraging the growth of the native desirable species has proven to be the most effective method of control. 

Chemical BMP: Herbicides such as Aminopyralid alone or in a product mix or in a product mix, Metsulfuron-methyl alone or in a product mix, and Tribrnuron-methyl are registered for use.

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Himalayan Balsam — Impatiens Glandulifera

NOXIOUS: Himalayan Balsam is a summer annual that prefers moist soils and some soil disturbance. Stems are smooth, hairless, and usually hollow and tinged red-purple. Leaves are lance-shaped, with pointed tips and sharp serrated edges. They grow in whorls of three or opposite on the stem. Himalayan Balsam has large flowers that vary in shades of pink to purple and can be occasionally white. It has a shallow fibrous root system that is easily pulled. Mature seed capsules explode when disturbed and eject the seed up to 5m.

Gallery himalayan balsam 02

Mechanical BMP: Mowing can be effective if repeated because plants can grow new flowering branches. Himalayan Balsam is easily hand-picked due to its shallow root system. All mechanical methods are best prior to seed production due to the special nature of seed dispersal.

Chemical BMP: Currently there are no herbicides registered for use on Himalayan Balsam and due to its preferred habitat of riparian areas the use of herbicides in aquatic environments requires a specialized Alberta applicator certification and/or permits.

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Orange Hawkweed — Hieracium Aurantiacum 

NOXIOUS: Orange Hawkweed is a fibrous rooted, perennial herb with a milky latex in the stems. It prefers well-drained soil types. This plant develops a basal rosette before producing a flowering stem. The basal leaves are oblong/lance-shaped to oval with a short or no point, and narrow to a petiole. Both sides of the leaf surface are hairy. Leaf margins can be entire or toothed. Orange Hawkweed produces a dandelion-like red-orange flower, which grows in a cluster at the end of a long stem. The stem and the stolon are also hairy.  Hawkweeds reproduce by seed, and vegatively by horizontal aboveground stolon and underground rhizomes.

Gallery orange hawkweed 02

Mechanical BMP: Mowing before flowering will prevent seed production of taller plants but remains ineffective for vegetative growth due to stolon and rhizomes plant spread. Handpicking may be effective provided all the stolon and rhizome root structures have been removed from the soil. Cultivation will result in spreading the infestation.

Chemical BMP: Herbicides such as Hexazinone, 2, 4-D and glyphosate are registered for use on Hawkweeds. .

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Oxeye Daisy — Leucanthemum Vulgare, Chrysanthemum Leucanthemum 

NOXIOUS: Oxeye Daisy is a perennial that spreads primarily by seed, but also has rhizomes. It occupies
a variety of habitats and grows exceptionally well in nutrient poor soils. Oxeye Daisy has a white daisy-like flower growing on a smooth, frequently grooved and sometimes branched stem. The leaves progressively decrease in size upwards
on the stem. Basal and lower leaves are lance-shaped with ‘toothed’ margins and are alternately arranged.

Gallery oxeye daisy 02

Look alike: Scentless Chamomile. 

Mechanical BMP: Horses, sheep and goats will readily graze Oxeye Daisy. Cattle however, avoid Oxeye Daisy but when used in a high stock density and short grazing periods can encourage cattle to graze and trample the plant. Trampling can also bring dormant seeds to the surface and under normal conditions; those seedlings will dry-out and perish before becoming established. Repeated mowing prevents the spread of seed, but can promote re-sprouting of stems. Hand picking is most effective when the rhizome roots have been removed. Due to the nature of Oxeye Daisy’s shallow root system, intensive cultivation will control an infestation. 

Chemical BMP: Herbicides such as Aminopyralid alone or in
a product mix are registered for use.

Gallery scentless chamomile 01

Scentless Chamomile — Tripleurospermun Inodorum

NOXIOUS: Scentless Chamomile can act as an annual, biannual or a perennial. This plant grows from fibrous roots and is established very quickly on disturbed sites. It continually blooms, forms seed and seeds out throughout a single growing season. This plant can produce up to 100,000 seeds per season, which can lay dormant in the soil for 20 years. Identifiable by its white daisy-like flowers and alternate leaves that are very finely dived into short segments (carrot-like).

Gallery scentless chamomile 02

Look alike: Oxeye Daisy, Pineapple Weed.

Mechanical BMP: Cultivation in the late fall and early spring will control emerging plants. Frequent shallow tillage can exhaust the seed bank. Mowing Scentless Chamomile can prevent seed production; however plants will re-bloom below cutting height. Hand pulling Infestations can
be the most effective.

Chemical BMP: Herbicides such as Aminopyralid alone or in a product mix. Chlorsulfuron, Clopyralid alone or in a product mix, Metsulfuron-methyl and Tribenurin-methyl in a product mix. There has also been a seed-head feeding weevil, Omphalapion hookeri, and a gall midge, Rhopalomyia tripleurospermi, released in Alberta for biological control on Scentless Chamomile.

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Tall Buttercup — Ranunculus Arcris

NOXIOUS: Tall Buttercup is a perennial and only reproduces by seed. It inhabits moist to well drained soils. It’s easily spotted by its bright yellow flower that grows on long stalks, and has 5 petals that are shiny in appearance. The leaves that are lower on the stem are deeply divided into 3-5 lobes. The leaves that are higher are smaller, hairy and divided into 3-4 narrow segments. Tall Buttercup contains bitter, irritating oil called protoanemonin that is toxic to livestock and other grazing animals when fresh stems and leaves are consumed. 

Gallery tall buttercup 02

Look alike: Oxeye Daisy, Pineapple Weed.

Mechanical BMP: Tall Buttercup can be outcompeted by planting a desired species in pasture or cropland scenarios. Maintaining a good grass stand in a pasture can also reduce the infestation levels. Pastures that have a severe infestation
can be cultivated and reseeded to an annual crop for several years as Tall Buttercup does not persist under cultivation. Mowing can be effective for small areas and infestations. Handpicking can be utilized for individual plants, provided gloves and long sleeves are worn as the plant contains juices that can cause skin irritation (blistering and redness).

Chemical BMP: Herbicides such as Aminopyralid alone or in a product mix, MCPA alone or in a product mix, Mecoprop and Tribenuron-methyl are registered for use.

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White Cockle — Lychnis Alba Syn., Silene Alba S. Latifolia

NOXIOUS: White Cockle is an annual, biennial and short- lived perennial. It habitats full-sun, well-drained soils and has male and female flowers on different plants. This plant emerges from an initially formed taproot, and then grows spreading lateral roots. White Cockle produces white flowers that have 5 notched petals with a tubular calyx at the flower base. The male flower has 10 veins on the calyx while the female flower has 20. The stems are hairy and swollen at the nodes, the leaves are opposite on the stem, hairy and slightly oval-shaped with pointed tips. 

Gallery white cockle 02

Look alike: Night-flowering catchfly (upper stems are hairy and sticky vs White Cockle is not sticky).

Mechanical BMP: Cultivation will spread an infestation. Frequent mowing will reduce seed production. Handpicking will work for individual plants and smaller infestations, provided the roots are fully removed from the soil. 

Chemical BMP: Herbicides such as Mecoprop or in a product mix, Tribenuron-methyl alone or in a product mix, are registered for use.

Gallery yellow toadflax 01

Yellow Toadflax — Linaria Vulgaris

NOXIOUS: Yellow Toadflax is a perennial plant that can reproduce by seed but relies primarily by sprouting from its rhizomes. Yellow Toadflax is frequently found in sandy-gravely soils but it has adapted to a wide variety of growing conditions and soil types. Stems are straight, hairless and
the leaves are soft, lance-shaped and very numerous. They are mainly alternate on the stem but can grow as opposites on the lower stem due to overcrowding. Its flowers are bright yellow, arranged alternately in dense spikes and have a long spur extending from the base of the flower.

Gallery yellow toadflax 02

Look alike: Dalmatian Toadflax (has broad, heart-shaped leaves).

Mechanical BMP: Repeated cultivation can effectively destroy the root systems. Hand-pulling and mowing can also prove effective by removing all roots from the soil. 

Chemical BMP: Herbicides such as Acetic acid, Amitrole, Dichlorprop, Diuron, Glyphosate, Hexazinone, Imazapyr, MCPA, Metsulfuron-methyl, Picloram and Trienuron-methyl an Thifensulfuron-methyl (in a product mix) are registered for use.

Weed Control: Rural Mowing

Rural Mowing is a part of our Integrated Weed Management Plan for Municipal District of Lesser Slave River No.124. The mowing activities keep roadside vegetation short to improve visibility and to ensure proper drainage. Mowing widths may vary from the edge of the road and depend on slope, obstructions and wet areas.

  • Range roads and township roads are mowed twice per year, between May and September
  • Rural hamlets are mowed a minimum of once per year, potentially twice depending on weather
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