P.S. The soil in that corner is loaded with clay, if that makes a difference.

Hard to say what your groundwater conditions might be without knowing the context of your neighborhood, elevations, contours, etc. Maybe you could post a pic or two of the area. Are you at the bottom of a valley? Are your neighbors higher or lower?

Hmmm ... I would dig a few holes. Maybe 1', 2' and 3' deep. see if they collect water and get a better feel for the soil structure. Is it mostly clay? Will anything grow there (that will help dry it up).

*sigh* my post wasn't posted until hours after I read it. Now i see the "mostly clay" comment. Can you dig down a few feet and heavily amend the clay with coarse sand?

I have some completely shaded, mostly clay areas that take much longer than a month to completely dry out once thoroughly saturated, even with french drains.

I was going to say the same thing as socalgal. I have some areas under heavy shade with lawn growing in heavy clay, and if the temps are moderate (in spring) it stays damp all the time.

Having soil that never completely dries is not "normal" and might indicate a problem or might be the result of a high water table. The simplest thing to do is eliminate that high water table by asking your local unit of government about that. Then, is your water supplied by your local government and does the supply pipe go through that area? Is your sewage discharge in that area? If none of these apply then there is another reason for that soil staying moist and putting down more soil will simply hide the problem.
If the soil is lacking adequate amounts of organic matter that soil might be too compacted to allow excess water to drain, a fairly simple explanation.

I know you didn't mean in that way kimmsr but I had to chuckle about the government fixing the water table. Have you seen Florida lately? LOL

Thanks to all of you for your replies!

Our house sits at the top of a cul de sac. I wouldn't say the ground is "elevated" as in it sits on a hill, but there's a very noticeable downslope from the house to the street and in the backyard, to the woods.

We did dig a 1' hole in that corner to see if it would ever dry up. There was a huge chunk of clay there, so I know the soil is very clayish. The moistness where we dug has dried a bit, but it's still moist to the touch. Not wet, not soggy, not damp....just moist.

We had a contractor friend come out and look at it a couple of days ago. He was totally stumped by it. He said if there was a leak of any kind there, the hole would keep filling with water. Well, the hole isn't filling with water at all; the soil just feels "moist" there. He said if there was a leak, you would be able to take a handful of soil and when you squeeze it, water would come out. That's not the case at all.

He adivsed us to leave it open for a couple more weeks to see what happens, then amend it heavily before putting the dirt back. We also would add more soil and mulch to that area. There's a shrub there and he seems to be doing okay in that spot, but I think I'll get some ferns or something that likes moist soil and see how they do there.

So, unless our water bill is completely out of whack, I guess I'll just keep on keepin' on. :-)

Thanks!

Yeah, I was not very clear about the high water table information. Your local unit of government should have information that will tell you if a high water table could be the problem, but usually they won't fix that although around here we have a county drain commission that is responsible for moving excess water away, after we pay a lot of money to create and maintain those county drains.
I do have areas, even in my very sandy soil, that because of the high water table are often quite wet late into the summer. Sometimes a good solution here is lots of organic matter, but not in excess which can make that worse by holding evenmore water in that soil.

I'm a bit stumped too. I don't know if you're having drought and heat this summer the way we are in MO, but we have no dry clay even in the shade right now. More like cracks you could lose a shoe in.

If it's very dry everywhere else, it does sound like there is a water source. Are there any sewer lines, septic tank, water lines etc. near that area? It doesn't have to be a big leak that would make puddles, it could be a small one.

Or, it's just slow-drying clay on your northeast exposure.

I meant to say, we have no WET clay, even in the shade.

Could you have a natural spring there? I don't know anything about the geology where you are but springs are common here. They often arise when permeable rock, eg limestone overlays an impermeable layer eg clay. And they move around occasionally too. What happens when you dig down? Does the hole fill with water?

I have a shady yard and want to dry out soil i wont be planting in, along paths etc. will epsom salt work?