Columbine will bloom at various times during the season...

Another option is to go for a variety of color and texture in lieu of flowers. This can provide interest at all times.

Painted ferns, hostas, ligularia, carex, tricyrtis, etc...

under my trees i have widow's tears, violets, coral bells, beacan silver, spiderwort, columbines, hosta, bleeding heart, pulmonaria, astilbe, turtlehead (not completely shady where it's at), virginia bluebells, jacob's ladder, cosmos, zinnias, hens & chicks, and a few lilies

you can check my trade list- while I do not have seeds to trade anymore it will show you names of plants/ seeds that I have been growing in my shady garden.
One caution- no perennial blooms non stop from spring to fall. Have to supplement various plants that come and go into bloom, or appreciate leaf shape /color or plant shade loving annuals.