Mallow species aren't typically toxic to livestock, though caution is advised with consumption of Malva parviflora. Wildflowers, including some mallow species, may have adaptations such as defensive chemicals or physical structures like thorns to deter herbivores.
When considering the impact of wildflower species on livestock, it's important to differentiate between their toxic qualities and their defense mechanisms. The mallow species generally isn't toxic to livestock; however, specific species, such as Malva parviflora (little mallow or cheeseweed), may contain harmful compounds and should be consumed with caution. Livestock poisoning from consumption of malva species is rare but can occur if the animals consume large quantities.
Regarding defense mechanisms, many wildflower species have evolved various adaptations to protect themselves from herbivores. These may include structures like thorns or spines, or the secretion of chemicals that serve a defensive function or that might inhibit the growth of other plants nearby. Some plants do release allelopathic chemicals, which can suppress the growth of other plants, including their own species, to reduce competition.