A wonderful little perennial that really performs and won't over take the garden is Astrantia (Masterwort). The common name is not very pretty or descriptive but when in bloom I get more comments on this plant. It's a member of the Apiaceae family, which is the same family carrots, dill, parsnips, and celery share. When looking at the foliage you can see the resemblance to celery leaves. It blooms in shades of white, pink, rose to burgundy, obviously depending on hybrid. Very cold hardy it grows rather slowly. Mine started in 4' pots and after four years had only gotten 18" across. The above pictured is Astrantia major 'Ruby Wedding' which I grow in a mostly sunning location. Flowers stay on for a long time and unlike many of its relatives ( fennel, carrots) it doesn't reseed. Being very versatile it works beautifully with woodland looking plants like Hostas and Heucheras. Or for that English country garden look it blends nicely with Echinaceas, Larkspurs, Delphiniums, and Cosmos.