Haven't seen it and don't have anything like it. Keep digging it up, maybe in the end you can win or at least keep it at a minimum. Others might recognize it if you let one grow bigger and take another picture.

I searched the web using "tricyrtis weed" and came across only this:

“Do you know someone who can help me identify this horrible weed that has been haunting me for several years. It comes up every spring all over the garden. I have tried everything to get rid of it to no avail. The roots are quite deep (about 8 to 12 inches and are like large octopus tentacles. None of my neighbours have this weed. Thank you in advance...".

The writer certainly described my situation! And his plant looks exactly like my plant. Exactly. It was identified by the responder as Tricyrtis hirta. Problem is Tricyrtis hirta has bigger flowers and more colorful flowers than my weed. But I'm convinced it is a Tricyrtus. And I am left wondering how it came to be such a prolific pest in my neighborhood.

Could you locate a local master gardener, county agriculture extension, local botanical garden to ask? It would be good to follow up, and if you find out anything, let us know.

Maybe this: http://cesanmateo.ucanr.edu/

Click "About," to find "contact us."

TricyrtisAsian lily - its not a weed but it does spread

another look at this plant

The flowers don't look anything like Solomon's Seal. The flowers look more like this plant (Tricyrtis formosum ) but even smaller and less colorful.

Today I happened to talk to a neighbor two doors down and she is finding the same weed all over her property too. I pulled up a sprout two blocks away the other day (only the stem comes out, no roots, so probably a wasted effort) and Ive seen it out in the woodsy areas along roadsides, so it's definitely in the neighborhood. Since I've never knowingly let one go to seed that means it's a prolific seeder from afar, so I am resigned to an ongoing war against this bad guy.