Answer: This might be blue eyed grass of some kind, a Sisyrinchium. There is a photo and description here (although mine have never looked so full and heavily flowered and so your fireworks description made sense for this plant when I read it.) You may need to cut and paste the complete url to make it work correctly.
If that's not it, you might take a photo and consult with your local professional nursery staff and/or county extension, try to find someone who is very familiar with perennials. I hope this helps!
Q&A Library Searching Tips