|I live in a closely-grouped townhouse complex in Zone 9 (hot summers!). We have a nearly east-west facing - the sun rises in the back yard and sets in the front. On the north side of the house there is a narrow alleyway leading from the gate into the back yard, with a nine-foot fence. There is a bed alongside the house which I have heavily amended about a foot down with redwood compost and manure compost (the local soil is concrete-like clay). Due to the eave of the house and a birch tree directly east, it gets only the faintest freckling of sunlight for about an hour in the morning - if that. However, the sun does shine directly on the concrete path right next to it, so there's some reflection - it's full shade, but it's not DARK full shade, if that makes any difference.
I will be keeping the bed faithfully moist in the summer. In the winter, it does NOT drain well, although we're working on that, and the amending I've done may help.
With that scene set, what are my chances for happy, healthy hostas, astilbe, dicentra and columbine?
|Sounds to me like you've done your homework! The bed you describe should be just about right for your choice of plants. You might even have room to include violas, which will grow into lush clumps and help crowd out weeds.
Good luck with your new garden bed!