Goutweed, Aegopodium podagraria, is the latest vile thing to invade my garden. It's also known as bishop's-weed (which seems for some reason creepy), and snow-on-the-mountain (which is too nice a name). It is a herbaceous perennial plant, another devious Eurasian carrot-thing (Apiaceae), like this one:
Giant hogweed, very devious Eurasian carrot. ( Thoroughly, and literally, irritating.)
As a herbaceous perennial, goutweed dies away to its roots in the fall, then re-emerges in spring. But it cheats. It wakes up while native perennials sleep the regulation time. Goutweed ignores local custom, is a crass, botanical door-crasher
Goutweed sprouting, overrunning garden and lawn while more respectable perennials snooze the recommended 5 months.
I don’t know how it got into my yard. Perhaps, rat-like, it rhizomed its way under the fence from a neighbour's garden. Or maybe a shard of root was intertwined among the roots of one of my legitimate perennials --which one, I cannot say. It has been smothered.
The only solution to completely rid my yard of this pest is to dig it ALL out. Roundup also will kill it, but will kill everything else too. Plus, it’s Roundup.
No matter what I do on this side of the fence, like the rats, goutweed will linger on the other side, and when the soil is free and clear, return.