You are probably correct to suspect excessive rainfall as the culprit. I lost a number of shrubs last year as a result of the 75 inches of rain I received. Even though soil drainage is adequate during years with normal rainfall, the additional amount (50% greater) was enough to keep the soil saturated.
Saturated soil and warm temperatures promotes the growth of the pathogens, Pythium and Phytophtora Root Rot: Pythium and Phytophtora root rot attack a plant if there are fungal spores in the soil and the plant is overwatered, creating a high moisture level. Roots turn black and break. Leaves turn yellow and fall off, usually from the bottom up. There is no chemical treatment for root rot.

Check the roots of the ones you have, to determine if that was the cause. If so, drainage will need to be improved before replanting. The roots of Ilex cornuta 'Soft Touch' go down in the soil about 18 inches, so that is an area that should be well drained. Locating the plant on a mound of soil or in a raised bed will also improve drainage.

Contrary to what some believe, amending soil almost always results in worse drainage, not better. You should almost never amend soil when planting trees and shrubs.

Many years ago, the practice of amending soil was common. Even today, some old-fashioned nurserypeople still recommend it out of habit. However, current scientific knowledge clearly shows this to be a detrimental practice. There have been a blue-zillion posts on Gardenweb covering this topic, many books and articles written about it, gardening shows that explain why it's such a bad idea, etc...yet some still haven't heard. So, again, don't amend soil when planting trees or shrubs.

Georgia-rose's idea of using a mound or raised beds will work and is probably the easiest solution to a drainage problem.

Here is a link that might be useful: Planting a Tree or Shrub

You should almost never amend soil when planting trees and shrubs.

except possibly in a raised bed...it looks like I lost 4 purple pixi lorapetalum, and I think the very tall raised beds were not well draining enough....:(, especially mixed with freezing. I won't count them gone until spring, but they look VERY very sad...

thanks for the replies.
I guess part of the problem was after removing some yaupons and their roots that had been there for probably 30 years, I had holes that had to be filled in. What soil I was able to reuse I ammended with garden soil because I simply needed soil to fill in around the rootball and I figured some good garden soil would be better than ga clay. I'll raise the bed a little this year and keep my fingers crossed. Thanks.

I've been in the green industry now for over 30 years in Zone 8A of mid-Georgia. There is no one perfect method for planting shrubs. There are simply too many factors depending on soil type, soil moisture, drainage, and the water needs of a particular plant. For example, here in mid-Georgia many gardeners have rock hard clay. In this case, soil amendments, such as gravel, sand, and decomposed pine bark-based products are necessary to break down the compacted clay so that roots can break through and establish themselves. That being said, peat moss is not a good soil amendment for clay soils unless you are trying to retain extra moisture in raised beds for certain types of plants. Too, soil drainage is always extremely important. In soils that remain constantly soggy it will be necessary to improve drainage by either elevating the ground or through some sort of drainage system. Anyway, to say say that one should never amend soil when planting shrubs and trees is simply too broad a statement and simply not accurate. As I said, I have owned and operated a landscape design build firm for over 30 years and we almost always use soil amendments. With the type of soil that exists in our area it's a necessity for many types of plants and trees to thrive.