I don't know if you want only blue, but if not, I can tell you that Knockout roses are excellent performers. They are shrub roses and grow well, but tolerate pruning if needed. They are covered in blooms most of the season, have few, if any, pests, and come in several colors (red, pink, white, yellow). I have a row of eight of them along my terrace, and two single ones in my upper garden, all of those are red. I have three yellow ones in an area alongside my driveway. I am happy with all of them.

Hydrangeas are a classic for that style of house! If you can make the bed about 6' deep, something like Hydrangea paniculata Quickfire would be quite happy. Mine is in all day sun, and does just fine; they aren't as fussy about sun and water as H. macrophyllas like Nikko Blue. There other H. paniculatas in various sizes, both smaller (as small as 4' or so) and larger, and with denser or larger blooms, but I like the lacy blooms of Quickfire, the long bloom season (late June to frost here), the rosy fall color, and the stiff branches which will support clematis.

Here's my QF at the start of bloom with Clematis 'Little Bas':

It goes through a sort of pale salmon phase in August

on its way to full fall color.

Red-twigged dogwoods look nice in winter, and if you get a variegated leaf plant, it is ornamental in summer as well. Some of the larger clematis on a trellis of less than 1/2" diameter would look nice. You may want to edge the bed to keep grass out.

You might also want to consider moving your very large Rhodie elsewhere on the property where it has room to spread (shallow-rooted, so dig and then drag on a tarp) since it has the potential to get quite large, and replace it with a rhodie a bit more in keeping with the size of the space. If you don't want to move it, be sure to prune immediately after bloom ends so you don't take off next year's flowering buds, which form over the summer.

Climbing roses would work if you are willing to fasten them to a trellis since they don't cling on their own like clematis. Zepherine Drouhin is one that is almost thornless, blooms in spring heavily, repeats some in summer if it isn't too hot, and then repeats in fall until freeze. It is happy in full sun to part shade, pink and scented.