Weed of the Month: Scentless Chamomile
For this Weed of the Month, we’re sniffing out an invasive pest that’s all looks, no substance: scentless chamomile. Despite its looks, this weed is no daisy: it can harm livestock and overtake areas if left unchallenged.
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Scentless Chamomile Origins:
Scentless chamomile (Tripleurospermum inodorum (L.) Sch. Bip.) came to North America in the late 1800s, most likely as a decorative plant, and is native to Europe, Asia, and Northern Africa. Since making the jump, it has spread through the majority of North America, where it’s classified as a noxious weed in many states.
Scentless Chamomile: Plant Description
Scentless chamomile is an herbaceous forb in the Asteraceae (daisy/aster) family. At a glance, it’s easily mistaken for a variety of daisy species. Depending on the environment, stems can vary from 6 inches to 3 feet tall with green, pinnate leaves resembling dill. Scentless chamomile flowers from late spring to early fall with composite flowers, a yellow disk center, and outer white ray petals about one inch long.
Scentless Chamomile Habitat
Scentless chamomile has adapted and spread across much of the US, primarily across the north. It spreads by seed, usually thanks to human or animal movement, and it grows in disturbed areas, along roadways, along trails, and in pastures.
Scentless Chamomile Growth
Flowering from late spring to early fall, scentless chamomile can produce around 300 small per flower head and 300,000 per plant. It spreads solely through seeds, which spread through human movement, animals, wind, and a bit of luck.
Scentless Chamomile Management
Luckily, scentless chamomile isn’t the most competitive invader. Despite producing so many seeds, you can help keep it in control by maintaining a healthy plant population. When unchallenged, it can easily take over an area thanks to the abundance of seeds. This is especially an issue in pastures, since it can cause blistering on livestocks’ muzzles.
There are no biological control methods, but you can easily manually remove the plant thanks to the shallow root system. Mowing can help prevent flowering and seeding, just don’t do it if seeds are already present.
In case of a large infestation, herbicide treatments are effective. Spring and fall treatments of young plants are best, but you can also treat flowering plants to stop the seeds in their tracks. Read the label before using any herbicide. Contact TCWP if you have any questions about application rates or how to use an herbicide.