Like many people apparently, I always thought that ragweed was another name for goldenrod. Turns out that goldenrod is not, in fact, the bad guy of allergy season. Apparently, common ragweed grows around goldenrod and is the actual culprit but gets overshadowed by the big, showy yellow flowers. This is actually common ragweed. I keep thinking they look like carrot plants.
They are apparently very hardy, care little about what kind of soil they are in, and while not “invasive” as some plants are, they do spread fairly rapidly. These pics are of the early season plants. Later in the summer they grow flower-like bits. I’ll get some pics then, if I remember.