It sets off interesting branch formations on deciduous woody plants and extends the green of evergreen ones. Also evergreen and tending to fade into the woodwork by midsummer is Polystichum acrostichoides . The fronds lay down in a fairly orderly fashion and, other than collecting fallen leaves, remain visibly green. Any of the several evergreen ferns would give the same effect in the winter garden. One can't have too many ferns, in my opinion.
Cold weather brings on interesting color changes in many plants.
Lamiastrum galeobdolon is one of them. The dark green center of each leaf takes on varying shades of burgundy, making a tri-color leaf of green, pewter and burgundy. Particularly hard winters will brown the leaves and require some cutting back in spring, but they will look good all winter in milder areas. The foliage of Geranium macrorrhizum is evergreen for me. Where leaves are in sun, they turn marvelous shades of red and orange.