Be on the lookout for winter-blooming hellebore species. This typically low-growing, herbaceous perrenial sports showy, petal-like bracts that can persist well into the spring--much longer than its small flowers. Their color spectrum includes greens, creams, and even flushes of red and purple. The foliage is extremely frost-hardy and variable in its generally slender shape and verdance.
Hellebore (Helleborus spp.) also has a lengthy history in folklore. Known alternately as "witch weed" and "Christ rose", toxic hellebore (active alkaloid: helleborin) has been used in folk healing as well as poison-making. Its frost-resistance and winter blooms were thought to be evidence of magical constitution. Hellebore tinctures were also used as a treatment for "winter melancholy" for this very reason--an original treatment for what we've developed as seasonal affective disorder (SAD).
Ingesting helleborin causes diarrhea, vomiting, and nausea--it was never used as a purgurative for the weak, even in antiquity.