I have been battling eradicating this flower from a part shade flower bed for over a decade. It has green leaves outlined in white and sends up a flower stalk with a flower resembling Queen Anne's Lace. It sends underground runners which, when pulled, dug, or sprayed with Round Up, reappear. I live in southeastern Michigan.
There is only one way I know to get rid of aegopodium: move! Do it in the dead of night in the middle of winter and do it very quietly. Leave no forwarding address. My father-in-law gave me that stuff once. He even came and planted it when I didn't plant it fast enough for his taste. The man never did like me at all. Within 2 years, my lawn was full of it and so was the neighbor's lawn. We both owned mature maples, so the lawns were in full shade. We were still allowed to use Killex in those days (2-4D amine). That eventually got rid of it, but it took many massive applications. Selling, owning, exchanging and transporting that plant should outlawed.
I live in a climate intermediate between the two of you. My personal experience has been that I was given some ferns that apparently had some rootlets of this awful plant embeded in the fern rootstocks. Whenever a leaf sprouted I removed it. In two years the Aegopodium rootlets were depleated and no more leaves have emerged.
If an infestation is caught soon enough a nearly daily program patrolling for sprouts can be effective. The ferns came from a (distant) neighbor's bed he was giving over to the Aegopodium and Japanese Pachysandra. The Aegopodium is winning that war.
I've been infested with this darling for over ten years, so "catching it early" doesn't apply. I found a couple posts recommending Round Up for poison ivy and another product, but my folder somehow has vanished.
We have the un-variegated version, which is much more invasive. We don't use chemicals where possible. You can in fact get rid of Bishop's Weed, but it requires vigilence. First, be sure it doesn't start to flower -- cut off everything that looks like it might bloom. This is really really important, because it will spread all over by seed. But that is easy to do. Second, you need to pull it out, teasing out all the roots. Cutting it to the ground or yanking it won't do any good. It is best to very gently pull it up out of the ground, trying to get as much of the very long roots as possible. They are like spaghetti, and break easily. Ideally, do this after a soaking rain, because the roots will pull up more easily. Or wet the ground down thoroughly and wait a while. Also ideally, do this early in the season (but of course, do it anytime you spot this beast).
If it is wrapped around the roots of a valuable plant, you may have to dig that plant up and wash off the Bishop's Weed roots from its roots. Even a little bit of root will resprout. I have found, however, that if you keep at it, the new roots move closer to the surface and easier to pull. We got it completely out of one area; we are still working on a second. We've been at it for a long long time, but we haven't been consistent; it really takes diligence.
I'm afraid if I used Roundup I'd get it on nearby plants -- that it would take so much care I might as well just pull. Plus, I find the long roots will reveal new sproutings that I didn't at first see, and might not have painted with Roundup. But in any event, we try to avoid chemicals.
Honestly -- you have it easy with the variegated version, compared to the unvariegated version. Small comfort, I know.
Hi: I've known that plant for years as "Snow-on- the-Mountain, ..also called Bishop's Weed, I think, It is often used as an ornamental bed in front of ore along the sides of a house, and probably would grow most anywhere, unfortunately.
I make a poiuny of dead-heading any blooms that arise, so it doesn't also set seeds. They look a lot like Queen Anne's Lace.
The trouble is, it has a sort of jointed root, and any bits broken off in trying to remove it, can generate into another plant, So dig deep, try to lift, not cut nor break, and get any root-bit you see. I think the roots are whitish, if I remember rigfht, which helps. But it may take a couple of seasons.
We have been trying to eradicate ours s(the unvariegated kind) for over 20 years. We have gotten rid of bamboo, poison ivy, and any number of other invasives -- but we can't get rid of this one. I keeps coming back, hiding under other plants -- and it will blossom even close to the ground where you can't see it and shoot its seeds around and about. But even without the seeding, the roots are appalling. They look like white spaghetti. It is best to weed them after rain (or a few hours after watering them) -- they pull out better without breaking.
As I recall I used it without diluting it and I used my own spray bottle to control the amount I used. I agree about avoiding the chemicals but I can only fight a weed for a certain amount of time before I give up. I fought it from 1992 to 2006 and that was enough!
The poison should travel through the leaves and the roots so it "should" get the entire plant and runners. Try it every other day and please let us know how it worked.
It escaped one garden, where I really thought my digging worked, until it popped up in a tiny crack in the driveway. That's part of the despair in dealing with it. The RU worked there with just one spray.
The problem is that it has "infected" a long garden bed with lots of plants in it on an awkward slope, so it takes me hours to work my way from one end to the other looking for signs of it. So I can't realistically do it every two days. Wish I could!