What are the dimensions of your backyard? Is it in total shade all afternoon?

One thing to consider is a small tree like Serviceberry. Many varieties are probably native to your area. White flowers in the spring, edible berries in summer, gorgeous fall color. Also it's not a super dense tree, so it won't block out light on you.

Bright colors and low maintenance? There are quite a few perennial flowers that fit the bill: daylilies, irises, coneflowers (echinacea), black-eyed Susans (Rudbeckia),or shasta daisies. For trees or large shrub how about burning bushes (can tolerate part shade), lilacs, peonies, or hardy hibiscus? These all like full sun.

For part shade how about hosta, columbine, pulmonaria, astilbes, ferns, or bleeding hearts. For trees or shrubs how about azaleas, rhododendrons, virburnum, dogwoods or serviceberry.

Thanks for advice everybody. I attached another picture that has the dimensions.

In the morning, about 5 ft of the yard at the left is in shade due to the fence. Around noon the whole area gets sun. Then later in the afternoon, the grass area at the gets sun while the deck area gets shade due to the house. Eventually, as the sun goes on the other side of the house, the whole area gets shade.