This picture shows the blooms of a heuchera that I have in one pot and the chartreuse leaves of another heuchera in a container I have positioned behind it. You can find heuchera in all different colors: various shades of green, peach, rose, gold, purple, and almost black. They all have wonderful names like creme brulee, tiramisu, obsidian, peach flambe, plum pudding, and solar power.
Heuchera is perennial and hardy to zone 4. It also likes part sun/part shade. It can tolerate full sun but you might end up with some slight scorching on the leaves. It blooms in the spring and early summer, but really, it's grown for its foliage.
When desigining a container, you can play up the color of nearby blooming flowers. For example, you could plant a heuchera with lime green foliage near a purple blooming plant. Or you can put several different heuchera in one container for an interesting foliage-only container. The possibilities are endless. This is a garden must.
Bookshelf: Container Gardening Books