If you want "true blue" and inexpensive, try scilla siberica. These should spread quite quickly into a large patch under your quince. Ipheion is more pastel in colour and does not give you as much "bang for your buck". It has a shorter flowering time as well. Anemone blanda (blue) flowers a long time and is also a "true blue". It may need slightly more moisture and shade than the scilla, but in the right growing conditions is a great groundcover. I grow both scilla siberica and anemone blanda but cannot remember if they bloom at exactly the same time or not. There is also a vigorous white anemone blanda as well called 'White Splendour'. Here is a link that might be useful: mass of scilla siberica

It's said to occur in Virginia though it's quite rare. V. perisca is in almost every state by contrast. Here is a link that might be useful: Veronica spp.

Duranta erecta 'Geisha Girl' or similar cv.

That's what I thought from the flower, but couldn't find any ssp. that looked like this. Unless I'm seeing it wrong... I was thinking the leaves would eventually become interrupted pinnate, like agrimonia. I'll look again.