Ranunculus ficaria/ Ficaria verna

Bright glossy leaves in spring, with bright yellow flowers. It goes dormant in summer. It grows very well in shade around trees.
This plant is incredbly agressive, and persists and spreads by making tiny tubers. Don't bother pulling leaves or mowing as the tiny tubers are left behind. A patch in my neighbor's has spread over the years into my yard, and accidentally I have carried it across to other parts of my gardens. The emerging plant will have tubers under it, after bloom it makes runners that will try to make new tuber bearing clumps.
The only saving grace of this invasive is that it has a fairly short period of the year that it is present with leaves and flowers, and I don't know that it can really choke out many other plants.