The native range of the annual fleabane runs from Canada, USA, and Nicaragua to Panama. The species has been introduced to much of Europe, as well as to several East Asian countries, including Korea, where it's considered invasive. It naturally occurs in waste areas and disturbed sites and tends to invade similar habitats outside of its native range.

Annual fleabane may cause dermatitis if its juice, sap, or thorns contact skin, leading to symptoms like red, itchy, or blistered skin. Toxic to cats and dogs if ingested, causing potential poisoning symptoms such as vomiting or diarrhea. Immediate veterinary care is essential for pets that consume any part of annual fleabane. Protective equipment is advised when handling this plant.

Annual fleabane is native to North America and is categorized as invasive in parts of Asia and Europe. The plant is recognizable by its daisy-like clumps of flowers and sudden appearance in gardens. Its unsightly leaves and crooked stems exude the appearance of a weed, which can greatly detract from the look of an ornamental garden. Annual fleabane is also an aggressive spreader due to its high re-seeding rate and ability to self-pollinate. The plant directly competes with other plants in the vicinity, causing problems for native species and vegetable beds alike. Manually pulling for a couple of years will wear away the root system and lead to elimination.

The best season for the removal of annual fleabane is in early spring before it has a chance to flower and set seed. This is typically before mid-summer.