Could it be Doronicum spp. (leopard's bane)? Are the flowers shaped like daisies? Or perhaps more likely marsh marigold, Caltha palustris? If you Google either of those botanical names, you'll see photos, which should tell you if your plants are either of those.

aaron uk i.d.'d it just now- on the name that plant forum .hooray!, but when i google it, i get no info about it-just photos.know anything about it-good or bad? thank you.

now that i've googled the correct spelling-(photos of it were misspelled ' ran. fUcaria' in webshots), here's what i've learned. soon to be R.I.P.ped out!!

fig buttercup
Ranunculales > Ranunculaceae > Ranunculus ficaria L.
Synonym(s): lesser Celandine
Lesser celandine is a short (up to 12 inches) herbaceous perennial that invades forests throughout the East, Midwest and Pacific Northwest regions of the United States. The basal leaves are dark green, shiny, and kidney- to heart-shaped. Flowers are showy, bright yellow, with 8 petals. It emerges very early in the spring with infestations often creating a green blanket along the forest floor. Lesser celandine invades moist forested floodplains. It is a spring ephemeral and grows vigorously, creating dense mats that exclude all other vegetation. It is a threat particularly to the native forest spring ephemerals that have to compete for light and space with this invasive. Lesser celandine is native to Europe and was first introduced into the United States as an ornamental. It is currently sold and widely planted as an ornamental.

Yikes, it's a monster! Glad I read this thread.

I thought my neighbor had planted Leopards Bane, which has spread all over my yard, but it looks much more like Lesser Celendine. The guy next door, who planted it all along the border, has a sign on his truck that says he's a Landscaper.

Pretty, but awful.

Here is a link that might be useful: Plant Conservation Alliance

Just be aware as you're ripping that celendine is a poppy relative and has a bright yellow juice that may be a skin irritant and is definitely staining to skin, clothing, etc. However, it is pretty easy to rip out, though you may need to continue to do so for years. (We've been in our place for 8 years, and I'm still ripping out a fair amount every year.)