“it's taken over an entire section along one edge”

Nuff said……

I think it's a biennial, so maybe if I chop down the plants before they go to seed that will reduce the population. I can easily do this with a string trimmer. ?

Can you show a picture so we can identify it first? There are several.plants colloquially known as QAL.

You can see it has the small purple spot in the middle:

In the US, QAL refers to Daucus carota. Although widely naturalized and for many years, it is considered an invasive species in many areas, including listed as a restricted noxious weed by the Michigan Department of Agriculture. I'd suggest removal ASAP.

Yup. That's D carota. But we have had US posters complaining about QAL and when they showed a picture it was Aegopodium podagraria. So a definite id is useful.

Yeah, just strim it back (I had the same with hogweed and hemlock all through the woods - one lot of strimming sorted it out (although there will be a seedbank so you will need to do this for a few seasons). No need to go mad with sprays or massive digging seshes.

I started on it yesterday, nowhere near finished hacking it down, maybe 1/8 of the way done. There's *a lot* of it. The hedge trimmer made faster work of it than the string trimmer. I had to take the time to rake up the debris, otherwise it would be an ugly brown mess from the house; I couldn't get it all of it raked because the other plants are getting high, too, but good enough. I did some hand-pulling in some areas -- they came out surprisingly easily, probably from the abundance of rain we had the day prior.