It is usually not considered a weed in California and is included in the table below for identification purposes only. Dalmation toadflax is an invasive perennial from Southern Europe. It was brought to California as an ornamental in the late 1800's due to its showy yellow flowers. It quickly escaped cultivation, and is now found throughout the state. Dalmation toadflax is adapted to a wide range of soil and environmental conditions, but thrives on coarse textured well-drained soils in open areas along roadsides and in rangelands and some cropping systems.
Disturbance appears to be closely related to the invasion potential of dalmation toadflax.
Initially, seedlings are poor competitors and establishment is difficult where competitive vegetation is present. However, established plants compete very strongly for limiting resources. Dense stands reduce grazing capacity and may displace native plants. Seeds are very small and are adapted for wind dispersal. Dalmation toadflax has an extensive underground network of lateral roots with numerous dormant root buds.