So much is made of evergreens for winter interest and few folks think of perennials in the grey and brown season. There are some that are standouts whether there is snow on the ground or not!
Anything with “evergreen” (perhaps the better word here is persistent) gray foliage is great in the low light on winter. One of my favorites is lavender–my species is lavendula x intermedia ‘Provence’, quite a mouthful. But only certain lavenders are hardy in my zone, and in my wet clay, it’s a struggle to grow them at all.
Heaths and heathers (the erica and calluna families) are another plant that is great for winter interest, but they just rot away in my soil in no time, even in my raised beds.
My lavender has succeeded, I think, for two reasons. First, I read about what the french do with their grapes. They pile stones at the base of the plants to warm them up in early spring. Since I suspect my plants suffer more from the cold, wet springs that from the actual soil drainage or winter temperatures, I’ve begun doing this as well for any plants that need a little extra coddling.
Next, this plant overhangs the edge of the garden and is right next to a driveway. I believe the reflected heat from the driveway helps it survive the winter. The summer heat doesn’t bother is at all despite the fact that I find the driveway too warm to walk on while barefoot at times.
Another great plant that keeps its leaves–and even its fall color–is perennial geranium. This is growing in my neighbor’s yard so I don’t know the variety.
Sedum is probably the perennial that gets the most “press” for being a winter interest perennial. I don’t grow the upright varieties–too wet soil and not enough sun. This plant is in a neighbor’s mailbox garden.
These 3 perennials along would make a nice combination together or in a perennial bed. The payoff is that they are truly “four season” plants.