
They finally bloomed and I was able to identify it as cow parsnip.

I don't know if it's official, but I deem them to be invasive because they can really take over a riverbank.
Overall, it's not a very nice plant, although nature people have found uses for it.
Here are the good things:
The native Americans used the dried stems for drinking straws. The roots can be used to make a yellow dye. The leaves can be cooked in soups and stews and impart a celery flavor. An infusion made by soaking the flowers in cold water is supposed to work as a mosquito repellant. (See note.)
Here are the bad things:
The sap can cause skin blisters just like poison ivy, and you can become sensitized to it, so subsequent exposures of decreasing degree can cause worse symptoms. If you pick some of the plant for cooking the smell can be so strong you don't want it in your car. Once you get it home, it needs to be boiled in water and the water poured off several times to decrease the flavor intensity.
I say the bad outweighs the good, and we're hacking off the flowers and burning them before seeds can be formed.
Note: don't you wonder how someone figured this out in light of the fact that the sap is a skin irritant? Who would think to soak the flowers and rub that on their skin?