don't know the answer-
I'm only replying because no one else has!

You might try a regional forum, like Virginia Gardening or Mid-Atlantic Gardening.

Best luck!

By chokeberry, do you mean Aronia melanocarpa? To consider this a groundcover is a bit of a stretch - it is actually a shrub and can grow to be a good sized one in time. It does tend to sucker after becoming established but not aggressively so therefore it doesn't really have the low, real estate-consuming spreading habit common to most plants considered as groundcovers.

The euonymous is a good choice but prone to scale. I'd consider Genista lydia also for slopes - very hardy, tolerant of hot, dry conditions and a very early and bright bloomer. It won't hurt to include the aronia as well, but keep in mind this won't really perform as a groundcover. Spacing for the euonymus and the genista should be around 18-24", depending on fast you want them to cover.

I've included a link on groundcovers for W. Virginia that provides a nice list (read carefully....some plants are too aggressive or prefer shadier conditions) as well as information on how to plant and establish them.

Here is a link that might be useful: Groundcovers for W Virginia