Dalmatian Toadflax (Linaria dalmatica)
The attractive flowers look like spurred yellow snapdragons and its blue-green stems grow to nearly four feet tall. It spreads by seeds and roots.
Biocontrol is available and offers only fair control of this invasive weed. Select herbicides can offer moderate control when applied from spring through fall. The only way to make sure it is dead is to persistantly remove all plants by digging them out.