Excellent rock garden, Jennifer! If you feel the urge to drop by and re-do mine, I won't stop you.
Chelle, in answer to your question about seedling grasses, I don't recall any problems. Annual weeds pull out very easily. The gravel is more than a mulch. I think about 5 tons of gravel went into the bed. To make the bed, I excavated soil so that the gravel would be four to six inches deep. I should have gone deeper. At a perennials nursery I know, there is a raised bed filled several feet deep with gravel, and all kinds of plants love growing in it. The gravel is just road grade, sandy gravel dug from the local gravel pit. While it dries fast on top, it stays moist beneath the plants.