I've never had this anywhere in my yard before, but yesterday I noticed this patch along maybe a 15' section of the fence. It looks rather nice there right now but if it's garlic mustard, I've read it's invasive and don't want it taking over everywhere. Probably 40 years ago someone thought it was a good idea to cover that narrow strip of dirt with rocks, which are now embedded into the soil and horrible to try to dig anywhere. So I figure anything that grows that easily to fill it in is good, but not if it's invasive.

Definitely. Should be easy to pull up before it makes seeds, or hit it low with a string trimmer.

Garlic Mustard (Alliaria petiolata)

I'll probably pull it up then within the next few days. Maybe there was one plant I didn't notice last year in that spot to create that mass planting of them there. Thanks for the confirmation.

Yet another chore to add to my overwhelming spring list!

I found a single one yesterday at my place (((dead now)))

I spent about 3 hours today digging them up, and that about 15' turned out more like 25'. I've got another 10' to go tomorrow. The older clumps have really long taproots, so I'm trying to dig to get all of the roots, and I cringe every time one breaks off without the root.

I can see how they easily got missed last year to have so many now. The babies coming up are just a slender single stem shorter than the daylilies, so you don't even notice them unless moving leaves around. Evil things!