You could put down cardboard (as a weed barrier) and put wood chips on top. You would start Pachysandra in a ring around each tree and encourage it to spread. You'll need to top up the wood chips every year or so while you wait for the Pachysandra to spread and take over. As the old chips rot they'll improve the soil. If you want a lot of chips cheap, find a tree surgeon with a chipper truck, make an arrangement for them to dump a few truckloads there.

Any one who has a well established Pachysandra bed probably has extra. Maybe you could find someone and make them an offer for some at a more modest price? Maybe on Craigslist?

Thank you for your reply, Ken.

I looked into the wood chip idea, and I found a subscriber service in my area where they pair you up with tree cutters and they'll drop off 20 cubic yards for free. I'll definitely need 2-3 loads of it, but I certainly can't argue with the price. The only concern I have with wood chips is the runoff where the next grand canyon is forming -- it is a veritable river when it gets flowing (see photo for alternate view). I read that with chips you normally put down 4-6 inches of it on bare dirt. Would that be enough to prevent rushing water from carrying it away? Or would I be better off building a temporary drainage system to route the water under the tree bed until the plants can grow outward and hold the soil together?

I guess I wrongfully assumed that I would need to plant the pachysandra all over the area, but your suggestion about letting it grow outward over several years sounds much more logical. Patience will be key.

Thank you again for your reply. You've definitely given me a silver lining on what I thought would be a daunting and expensive project!

I looked into the wood chip idea

I just got a fresh truckload of them for Spring. A few things you can expect: The chips are rougher and coarser than store bought. If this bothers you, you can throw down a thick layer of the cheap stuff and then a thin coat of expensive ones on top. they come in various colors. After a while if you dig around in it you may see white/ off white threads running around in it, or worms crawling around down there, or even mushrooms on top of it. These are decomposers. They are busy changing it from wood chips into plant food. They won't bother you or your plants, they only like dead things. The chips start off a brightish white and fade slowly through grey and get soft and blackish as they meld into the soil.

The only concern I have with wood chips is the runoff where the next grand canyon is forming -- it is a veritable river when it gets flowing

A valid concern. Can you run a heap of rocks down the canyon for the water to flow through without moving them? Maybe have a series of lashed stick dams to let water through but hold the chips? Lay branches across it?

I read that with chips you normally put down 4-6 inches of it on bare dirt. Would that be enough to prevent rushing water from carrying it away?

I'm not sure.

Or would I be better off building a temporary drainage system to route the water under the tree bed until the plants can grow outward and hold the soil together?

Maybe lay a perforated pipe on top of the ground, bury it in chips?

I guess I wrongfully assumed that I would need to plant the pachysandra all over the area, but your suggestion about letting it grow outward over several years sounds much more logical.

There are various ways to handle this.

The rings were meant to give you something decorative, something orderly to look at while it's developing. You could plant them in a loose even scatter across the whole bed. This won't look like much at first but might be faster.

You could buy and install more plants whenever it's convenient (you just move the chips out of the way and plant) You could subdivide and move the existing plants every few years. You could plant once and let them do their thing. They'll all work.

Looking at the the second picture I see I misjudged something. I had thought the trees were centered in the bed. They're not, they're along one edge. This means a ring around each tree won't be starting them in the middle, it'll be starting along one side. This is not a deal breaker. You could do rings around the trees and start some sprinkled along the left side of that second picture so it keeps up with the tree side.

Patience will be key.

The rule of thump with Pachysandra is:
The first year it sleeps.
The second year it creeps.
The third year it leaps.

Thank you again for your reply. You've definitely given me a silver lining on what I thought would be a daunting and expensive project!

I love it when this Internet stuff works. 8-)

You are truly amazing, thank you Ken for such a thorough response. I'm going to start by taking out the weeds that are there now (I put down a dose of pre-emergent, and will follow up with some larger area weed killer. By then, hopefully I'll have gotten the delivery(ies) of chips.

Coincidentally, I took the kiddo to visit the grandparents this weekend and lo-and-behold, my mother had an overgrown patch of pachysandra in the backyard that she was dying to cut back! She lit up when I told her about this project.

I hope to be able to post a follow up picture in a month or so once the legwork is all completed. I may just have to put a sign out in the middle of it that reads, "Transformations by Ken" :).

I have been thinking about your point # 2

2. Erosion control from the run-off on my neighbor's property coming from the right hand side of the photo towards the trees.

We were talking basically about getting rid of the water, scooting it out of your property to get free of it. If you care to, I think we can do better. Rather than get rid of it, how about using it?

I seem to recall that Georgia had a pretty good drought in, was it '07 ? If there was one, there could be another. To a gardener they are annoying, but you could be prepared.

What would you think of running a few berms across the bed so that it becomes one or more small swales? You don't need to get huge or expensive, or fancy. You just run a low line of rocks and dirt across the stream bed and encourage some of the water to pool and sink into the earth. Once the ground is shaped to your liking you would plant and chip it just as you were going to anyhow. About the worst that could happen is that now and then some of your chips would float for a bit.

The overall effect is that when water is plentiful you would be storing some of it in your ground. If you keep everything low it should be pretty close to invisible once the chips and plants come in. You are not trying to fight against or stop the water, you would just be putting some aside against the future. When it is needed your plants will find it.

Look into Big Root Geranium, handsome groundcover that will be evergreen in your area. It's in bloom now in mine. Spreads slowly but is very easy to keep under control and isn't expensive. A start of several plants would get you going and in the following year you can pull rhizomes and put them in between the started areas.