Vectors of spread:
General: Scentless Chamomile is an odourless, daisy-like flowering plant that is annual, biennial, or short-lived perennial.
Flowers: The flowers resemble daisies, with white petals and a yellow centre. They are approximately 2-3 cm in diameter, and there is a single flower at the end of each branched stem.
Stem: The stems of mature plants range from 0.15-1 m tall, and are smooth and branched. Scentless Chamomile plants tend to be bushy when not subjected to competition, or after having been mowed.
Leaves: The leaves are finely divided into short, thread-like segments. The “fern-like” appearance of the leaves distinguish Scentless Chamomile from Oxeye Daisy, a similar invasive species.
- Oxeye Daisy (Leucanthemum vulgare): The leaves of Oxeye Daisy are broad and coarsely-toothed.
- Wild Chamomile, Stinking Mayweed, or Pineapple Weed: The leaves have a strong odour when crushed.
- Corn Chamomile: Has stems that are hairy below the heads.
Habitat and Origin
Native to Europe, Scentless Chamomile was introduced to Canada in the 1930’s as both a garden ornamental and a seed contaminant.
This plant is commonly found along transportation corridors, fencelines, and other disturbed sites. Preferring high moisture content in soils, Scentless Chamomile can often be spotted near ponds, streams, and other areas prone to seasonal flooding.
Propagation and Vectors of Spread
Scentless Chamomile propagates by seed, of which a single plant can produce up to half a million. The seeds germinate under periodic flooding conditions and can even float in a water body for as long as twelve hours! Therefore, they are easily dispersed by water, as well as wind, crop seed, and animal feed.
Large infestations of Scentless Chamomile along transportation corridors can be primarily attributed to wind dispersal, and can serve as a major source of spread to adjacent agricultural areas and aquatic systems.
Ecological and Economic Impacts
Scentless Chamomile crowds and competes with native vegetation, and forms monocultures near water bodies or riparian areas, on sites with heavy soils and high soil moisture, or in soils that are subjected to periodic flooding. Its versatility as an annual, biennial, or short-lived perennial causes it to be an extremely difficult invasive plant to control.
Scentless Chamomile forms dense stands and can negatively impact pastures, cultivated crops, and grain, seed, and hay fields by reducing crop yield.
What Can I Do?
Scentless Chamomile is found throughout the Sea to Sky region, so PREVENTION of further spread is key.
Learn to identify Scentless Chamomile: use the images presented in this profile page.
What to do if you spot it: You can report any Scentless Chamomile sighting by clicking here.
Play, Clean, Go. Remove plant material from any equipment, vehicles, or clothing used in areas with infestations. Wash equipment and vehicles at designated cleaning sites before leaving infested areas.
- Regularly monitor properties for weed infestations.
- Ensure soil and gravel is uncontaminated before transport
- Minimize soil disturbance in area surrounding infestation
- Ensure plants (particularly flowering heads or root fragments) are bagged or covered to prevent spread during transport to designated disposal sites (e.g. landfill).
- Plant Scentless Chamomile in a garden, no matter how well-contained its enclosure may seem.
- Move soil or gravel that has been contaminated with Scentless Chamomile.
- Compost any plant material.
- Unload, park, or store equipment or vehicles in infested areas.
- Mechanical control options, such as hand-pulling, are effective for small infestations of Scentless Chamomile.
- In addition, mowing can reduce seed production. However, it should be done early and then again before the plant has flowered, with each successive mowing treatment lower than the previous one.
- Herbicide applications are most effective early in the season before flowering, but can be done throughout the season as long as plants are green and growing.
- Effective herbicides include aminopyralid, metsulfuron methyl, dicamba, 2,4-D and picloram; however, picloram is not suitable for wet, coastal soils.
- We recommend that any herbicide application is carried out by a person holding a valid BC Pesticide Application Certificate. Before selecting and applying herbicides, you must review and follow herbicide labels and application rates; municipal, regional, provincial and federal laws and regulations; species-specific treatment recommendations; and site-specific goals and objectives.
A seedhead weevil (Omaphalapion hookeri), stem-boring weevil (Microplantus endentulus) and adult gall midge (Rhopalomya tripleurospermi) have been released in northeastern BC.
- Alberta Invasive Species Council, https://abinvasives.ca/wp-content/uploads/2017/11/FS-ScentlessChamomile.pdf
- Invasive Species Council of BC, https://bcinvasives.ca/invasives/scentless-chamomile/
- Invasive Species Council of Manitoba, https://invasivespeciesmanitoba.com/site/index.php?page=scentless-chamomile
- Government of Saskatchewan, https://www.saskatchewan.ca/business/agriculture-natural-resources-and-industry/agribusiness-farmers-and-ranchers/crops-and-irrigation/weeds/scentless-chamomile
- Ministry of Transportation and Infrastructure of BC, http://cccipc.ca/documents/ManagingInvasivePlants.pdf