All Ted and Nancy Dobson wanted was a simple container garden. But when my partner and I first met with them, we discovered that the Dobsons’ backyard looked more like the bottom of a swimming pool than a patio. It was a little space, with house and garage walls on one side, a shoulder-high retaining wall on the other, and a river of concrete in between. The tight dimensions made the yard feel closed in, and we couldn’t remove the paving due to drainage issues. The Dobsons hoped, however, that adding several pretty planters would, at least, soften the look. Although it would have been simple enough to install a container garden, we knew that none of us would be ecstatic about the results. This property presented some imposing challenges, which were beyond the help of planters. We solved almost every problem at once, however, by building an elevated garden…