Dalmation toadflax is a wide spread invasive. The extent of it’s spread can be seen in this map from the Natural Resources Conservation Service.
Originally brought to North America from the Mediterranean region of Europe as an ornamental, Dalmatian toadflax is currently found in at least 34 states in the U.S. and most of the Canadian provinces. It is most widely distributed in the western U.S. and Canada.
Isolated plants can be dug up fairly effectively if the soil is not too hard or rocky. However, roots tend to break off and new shoots will re-sprout from any remaining lateral roots. Make sure to follow up at the site for at least a few years to watch for re-growth from the roots and emerging seedlings. If plants are in seed, carefully bag and cut off the stems before digging up the roots to minimize seed dispersal.
Information from King County Washington.