Thanks, everyone, for your comments. It took a lot to even get this area ready for planting. When we bought the house at the end of 2008, there was ivy, plumbago, a bougainvillea, and lots of weeds on it, and there were rocks and cement and bricks buried below it. Here's a picture of it in August, 2008:
These were some of the rocks that I had to dig up in June, 2009, to get ready to start planting:
Here is how it looks now:
