Dalmatian toadflax was introduced in the U.S. for ornamental and medicinal purposes. Quakers relied on the plant for liver and skin health. Plants boiled in milk were set out in settlers’ homes to eradicate flies. But as with most invasive plants, what began with the best of intentions got out of control. The plant found a new home in rangeland type soils. Once established, it pushes out the native vegetation. While the plant may not be toxic to livestock and wildlife, both tend to avoid it. It has zero food value.
It is difficult to eradicate: The plant has an extensive root system that can extend six feet or more. New plants will regenerate from the roots. Seeds can remain in the soil for 10 years.
Herbicide can control the plant, and it is best done in late spring Weed pulling can be effective but will need to be done repeatedly in an area, making sure to remove the lateral roots. Mowing is ineffective because it will not touch the root. The Oregon Department of Agriculture also offers bio control agents to fight the Dalmatian toadflax invasion. A natural enemy of a plant (in this case Dalmatian and Yellow toadflax seed capsule weevil and Dalmatian toadflax stem boring beetle) are introduced. The insects are tested to ensure they will not become a problem on their own. The location is then monitored.