I have a similar trouble spot right behind our garage (sandwiched between three walls and a very large fir tree. Lamb's Ears love it. I don't irrigate there. Though some websites say that they are full sun plants, I haven't found that to be true at all:
http://davesgarden.com/pf/go/138/
I'd also suggest Box which I find it to be a very handy and hardy plant, very amenable to pruning.
Boxwood - Buxus sp.
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General Information: Boxes are densely branched shrubs native to Europe and Asia. A hedge steeped in history, box sprigs have been found in the tombs of Romans. It is widely used as a hedge plant, and is a common topiary subject. Most varieties of box are marked by a distinctive "foxy" smell which some find distasteful. The box is an important plant commercially, as it is one of the few woods heavier than water, and is thus used for making woodcuts and precision instruments.
Most boxes are grown as hardy bonsai, but the Harland box has been successfully grown as an indoor plant. Box is very popular for bonsai due to its tiny leaves and flowers and its tolerence for extensive pruning and shaping. One note of caution: box leaves are poisonous, and eating even a few can kill a small pet.
Lighting: Box is not particular. Sun or shade both work well. Buxus harlandii prefers shade or semi-shade, and has an indoor light requirement of only 800 Lux.
Temperature: Hardiness depends on variety, but boxwoods need protection from frost and cold winds even when grown in the proper climate. In the summer, box appreciates fresh air.