Help identifying plant (North America - Midwest)

Question

I've been scouring the internet for weeks on this and am hoping for some help.

This plant is growing prolifically in a flower bed in my yard starting in late April. Below are three pictures of single stalk that I pulled up (I think this is a mature version of it at 2+ feet with serrated leaves and a cluster of small white flowers on the top).

This plant appears to grow through rhizomes based on my experience in pulling it up although it's possible that it's just so well-seeded that it appears as though the clumps are connected. The stems pull out of the ground easily but tend to break off at the root making it very hard to weed. Only a few have survived to the flowering stage you see above (due to intensive weeding efforts), but even before flowering, they can grow more than two feet tall and are shading and crowding out some sedums and lillies that did not emerge as quickly (which is why I'm designating it as a weed because it's aggressively crowding-out wanted plants). Additionally, I think I've come to the conclusion that I have a variegated version of this growing in a different part of my yard.

Summary

• Location: Illinois
• 2-3 feet tall
• Serrated, opposite leaves
• Small, clustered white flowers
• Fast growing (possibly via rhizomes?)
• Prolific (not uncommon to have 5-10 growing in a 1 to 2 inch area)
• Hollow stems
• Variegated variety exists

Picture 1: Entire Plant

Picture 2: Leaves

Picture 3: Flowers

Additionally, if you are familiar with it, any insight into controlling it would be greatly appreciated. Thank you!

Answer 1

It's the species form of Aegopodium podograria - also known as Bishop's Weed in Wisconsin. It is an extremely nasty invasive because, as you noted, it spreads via rhizomes, which are thin and easily broken. Any pieces left in the ground during removal will sprout a new plant if there is a root node on them.

The first thing you need to do is deadhead/livehead all of the flowers in the clump. Do not compost them - I'd either burn them or toss them in your garbage.

Control is a pain. It does not die from RoundUp, although it does get knocked back a bit. I've only had success manually digging it out - and note that this can be a multi-year project if the clump you have is fairly large.

My method works if the soil is somewhat dry but not rock-hard - unless you're on clay, in which case you want the soil a little damp. Insert a garden fork at an angle about a foot from one side of the clump and gently rock the soil with the clump. If the clump is small enough, do this around the entire clump; if not, try sectioning the clump and do one section at a time (the aim is to loosen the soil without breaking the roots). Next, insert the fork again and this time lift it a little to expose some of the soil on the fork. Use your hands to gently remove the soil until you get only a mass of roots. Repeat this until you've removed as many of the roots as possible from your clump of weeds.

The reason that this can be a multi-year task is because you'll inevitably miss roots or break them, and they'll sprout new plants. I'd plant annuals in this area until you are 100% positive that no more Bishop's Weed is present.

Answer 2

It looks like what I call "garlic mustard" a European invasive . Wikipedia shows some photos like yours and somewhat different. In the forest preserves in northern IL they are manually pulled by volunteers. I don't know if that is because it is resistant to herbicides or to avoid using herbicides in the preserves. It first showed up about 40+ years ago.