Only one this morning to start us off with the letter "F"....
Foliage color, most often when we think of foliage it is in relation to foliage habit, evergreen, semi-evergreen and dormant, or disease, rust, leaf steak etc. A few daylilies have variegated foliage with stripes of green and white or green and yellow.
Two threads that talk more about variegation...
The thread "Is there such a thing as a variegated daylily?" in
Daylilies forum
The thread "Foliage variation" in
Daylilies forum
What about shades of green and blue ? Hostas showing deep green and blue..
Daylily leaves in light green and dark blue-green.
Or frosted silvery blue like a fothergilla....