I finally took a picture of the white violas that sprung up in my daylily bed. I planted violas (Johnny jump-ups) last year in a bed that was on the opposite side of my garden, but this viola is white, not purple like the rest, and there are no nearby volunteer Johnny jumps ups, so this appears to be a truly wild viola, not a mutated volunteer from my seeds I planted last year.
If anyone can help ID this variety, please do!
P.s. please ignore my overgrown DL bed. I'm having problems with grass growing in it, which is very difficult to pull out (and it keeps growing back when I do).
