Scentless chamomile

Although native to Europe, scentless chamomile is currently found in all regions of British Columbia, but is a major concern in the Kootenay, Okanagan, Peace River, and Thompson areas. It is found on low to mid-elevation sites, along roadsides, drainage ditches, fence lines, dry shorelines, and other disturbed areas.  Scentless chamomile prefers areas with high soil moisture, well adapted to heavy clay soils  and  tolerates both periodic flooding and dry sites.  It is  commonly found near ponds, streams, and other areas prone to seasonal flooding.  The seeds float on water and are widely dispersed this way.  

• Scentless chamomile is an aggressive seed disperser. Seeds are readily dispersed by wind or water, on equipment and vehicles, or as a contaminant in soil, fill material, crop seed, and animal feed.  
• Seeds can float for 12 hours and new infestations are often found around watercourses. Transportation corridors serve as major sources of infestation and spread, and there is an increased risk of invasion to adjacent agricultural areas and aquatic systems.  
• Scentless chamomile can reduce crop and pasture yields.  
• Scentless chamomile can form monocultures near waterbodies, riparian areas, or on sites with heavy soils and high soil moisture.  

The most effective way to ensure that your lands do not become infested with scentless chamomile is by prevention. Here are some recommendations to prevent scentless chamomile from invading your property:  

• Avoid unloading, parking, or storing equipment and vehicles in infested areas.  
• Remove plants, plant parts, and seeds from personal gear, clothing, pets, vehicles, and equipment. Wash vehicles, including tires and undercarriage, and equipment at designated cleaning sites before leaving infested areas.  
• Bag or tarp plants, plant parts, and seeds before transporting to a designated disposal site (e.g. landfill).  
• Take special care when controlling scentless chamomile near streams or ditch lines to prevent the movement of plant parts downstream.  
• Maintain your crops and natural lands in a healthy, vigorous condition to ensure a competitive plant community. 
• Regularly patrol your property for scentless chamomile plants and immediately control or remove infestations before seed set.
• Do not leave plants to compost as they may still produce viable seed. 
• Cooperate with adjacent landowners and encourage them to prevent scentless chamomile spread. 
• Immediately re-vegetate disturbed, bare soils with a suitable seed mixture that provides dense, early colonization to prevent weed invasion. 
• Do not move contaminated soils to a new area. 

• Mowing can be used to reduce seed production in pastures, hayfields, and non-crop areas, and should be done early and often before flowers are formed. Each successive mowing should be lower than the previous one, as plants will form new flowers in the  leaf axils  below mowing height.  
• Frequent shallow tillage can be used to control seedlings if done during hot, dry weather and before plants flower.  
• Hand pulling small infestations before they go to seed can prevent new infestations from developing. Bury or dispose of plant material in a landfill.  
• Chemical control is also an option. 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. 
• Non-selective herbicides containing glyphosate are not recommended, as all vegetation on site will be killed, leaving no competition for new, emerging scentless chamomile plants.  
• Before applying herbicides, read the label for full use and precautionary instructions.  
• For further information on the selection and application of chemicals to protect your crop, contact AgriService BC at 1-888-221-7141 or email AgriServiceBC@gov.bc.ca 
• For biocontrol, a seed-head weevil (Omphalapion hookeri), a stem-boring weevil (Microplontus endentulus), and an adult gall midge (Rhopalomyia tripleurospermi) have been used in northeastern B.C.