Spotted Knapweed - blech!

Spotted Knapweed (Centaurea maculosa) is an invasive weed that has been pretty successful in its establishment on our front lawn/meadow. Once there was just one of them and I kind of liked its flowers and appearance - big mistake! I've been at war with it this spring/summer digging it up.

It looks like this now except that it is embedded in the grass.

Sometimes it just pulls up but usually I need an asparagus knife to dig it up since it's root is pretty solid. This tool is supposedly used to scrape asparagus stems, however I suspect that it is only used as a weeder - and a good one at that. I also used it to dig up some plantains and dandelions today.