Answer: Your best bet to cover the rocks is probably a vine. Fall blooming clematis is a good candidate, as is Virginia Creeper. Another might be the Trumpet Creeper. Keep in mind that all vines seem to take a year or two to settle in and then go ape. These are all deciduous vines which can be cut back should you need to get in to work on the rocks.
Thorny bushes to keep kids out might include barberries or rugosa roses. A fence might also work.
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