Amending the soil just in the planting hole isn't recommended. In clay soils in particular, it creates a pot-like or bath-tub effect because when water perks into the amended soil it has no way to drain. Even if the soil isn't clay, the roots of a shrub are less likely to grow from the amended soil into the native soil.

If I want to amend soil I usually do the entire bed. You can layer amendments on top of the soil and mix them in with the soil to make a somewhat raised bed which will drain more normally or at least allow a root run raised above the worst of the water. Or you can build a real raised bed large enough for shrubs.

I couldn't think of any shrubs that fit all of your requirements, and when I plugged all your requirements into the Missouri Botanical Garden plant finder no plants came back. Either you will want to compromise on some of your wishes, or perhaps you can combine shrubs and perennials to get evergreen and red flowers, just not all on the same plant. There are some short forms of white cedar, Thuja occidentalis, which is evergreen and is fine in wet to average moisture, but has no flowers. Some have gold or bluish foliage.

Some flowering plants that are happy in damp soil to standing water that have blooms in the pink range (not really red-fushia) include Clethra alnifolia 'Ruby Spice' or a pink form of Rhododendron viscosum, swamp azalea. The azalea blooms in spring and has nice fall color, and the Clethra blooms in late summer or fall and has clear gold fall color. Neither have a particularly long bloom period or are evergreen. Both will probably need pruning to keep in bounds. You may find some smaller pink forms of the Clethra.

Ilex verticillata, winterberry holly, is deciduous but has red berries all fall into early winter and like the Thuja grows naturally in swamps.

Rosa palustris, swamp rose, has pink flowers.

Red-twigged dogwoods are deciduous, but will have red branches all winter. Younger twigs have brighter bark, so you can prune some branches to the ground every year to keep it smaller and redder. Some forms have gold bark or leaves that are variegated with white or gold.

Cardinal flower, Lobelia cardinalis is red-flowered and likes wetlands. It flowers in late summer. Louisiana iris thrives in wet conditions, and has several forms with various reddish tones, though no really true reds. Both these are perennials.

nhbabs, thank you so very much for your effort to try helping me out as much as possible. Even though there is none fitting my preference exactly, the plants you mentioned would help me a lot to narrow down the choices to plant there.

And sorry that I forgot to mention that I did amend the entire bed, but not only the holes. The bed is kind of in the center of the lawn. I don't see standing water in the bed, yet there is a lot of standing water after a rainfall on the lawn. I just thought that the water would still run into the bed though. Thus, my loropetalum is not doing well...

Yes, if the amended bed is not huge it will still act as a collection point for water on a damp or wet site until any organic amendments used have rotted away and the soil returns to its original composition.

Putting the shrubs in the same soil they would have been in if you had not amended.

The smart solutions are to either choose shrubs that grow in damp clay or buy special soil for the shrubs you want to grow, dump it on top of the clay and plant them in that - without mixing any of the imported soil with the clay.

good advice, bboy. thanks