Purple Flowering Groundcover - Campanula Portenschlagiana - a plant that grows in less-than-ideal conditions and has long-lasting foliage. Plant care info is on the post - via Northern Shade - Gardening Daily
Purple Shamrock (oxalis) - Best in shade as front-of-bed edging or ringing a shade shrub such as hydrangeas or rhododendrons. Also nice in a shady flower pot. Companion plants: Under Ferns, Cimicifuga or Variegated Solomon’s Seal.
Zebra Hollyhocks are perennials that bloom all summer long. They are easy to grow self seed are drought tolerant and attract butterflies. They grow in sun to part shade and get tall. Great for perennial beds cottage gardens borders and rock gardens.
Dalmation Bellflower produces beautiful mounds of purple bell-shaped flowers from late spring through summer. Low-growing plant is perfect for adding color in front of other perennials. Grows only tall. Spreads Prefers full sun to partial shade.