Bleeding Hearts for zone 4. Bloom in spring and then cut back after blooming. Likes partial shade.
Creeping Phlox Candy Stripe zone 4. Flowers in the spring and stays green all summer prefers partial shade.
Pink Creeping Phlox zone 4. Flowers in spring and stays green all summer prefers partial shade.
Sedums, Hens and Chicks check and make sure your sedums you buy are for your area ours is zone 4 in Utah. Likes full sun.
Variegated Sedum zone 4 can plant in rocky soil and full sun.
Huechera or Coral Bells mine grow best in partial sun Zone 4. Look for foliage that you like on this plant that is there best asset except for the Ruby Bells or those with red flowers and they bloom in the spring also.
Purple Creeping Phlox this is the best one in my yard for survival it is a great bloomer. Zone 4 it grows like all the above creeping phlox.
Double Tulip
Dwarf Forsythia this is a shrub that blooms in the spring. Zone 4
Pansy
Lindy