Are you talking about putting in evergreen foundation plants or annuals?
We have the rock hard clay too. I hate it. We're going to try to amend it before we plant the Encores but we used to do that at the college where I taught horticulture and you know what? A year later, we'd take some core samples of the soil we'd amended and it would be all clay again.
Honeychile, the English ivy hurts brick because of the suckers it clings with. There are other vines that aren't quite as destructive to brick.