Sudduth designed the rock garden at the University of Georgia's Research and Education Garden. The garden is on the Griffin, Ga., campus of the UGA College of Agricultural and Environmental Sciences.

"With rock gardens, you're replicating the plants' origin to the best of your ability," Sudduth said. "You can localize the kinds of soil you use. You can put plants that need organically rich, well-drained soil next to not-as-sensitive plants that are just fine with a local clay soil."

You can put a sun-loving plant next to one that will wither under too much heat, too, if you build it a shade-heavy crevice.

Sudduth said rock gardens give experienced gardeners the chance to work out their green thumbs.

"They're are horticulturally challenging," he said. "But they're visually appealing. And they give gardeners the chance to try new combinations of plants. It gives them a place to indulge in their plant passions."

If a rock garden sounds like your next project, here are some basic steps to get you started.

Ideally, you want your garden to look like a rock formation being exposed by an eroding hillside. So look for a nice slope. Gardening on a slope ensures proper drainage, too. The site should also be clear of overhanging trees.

If all you have is flat land, you can create your own mounds with rocks or with soil covered over with rocks.

Sadduth says there's a good rule of thumb when selecting rocks for your garden. "If it only takes one person to carry it, you don't want it," he said.

Try to get local rock of the same color and type, too. This makes your outcrop look like it came out of the ground instead of out of the local home center.

Before you start arranging your boulders, take a look at some local rock formations to get some ideas. "You don't just want to make a pile of rocks," Sudduth said. "That's what we call a dog-grave garden."

Bury your rocks a few inches below ground level to aid in the illusion that they've been exposed by eroding soil.

You could pick your plants and then create microclimates specifically for them. Or you could place your rocks and then pick plants that match the microclimates you've created.

For a listing of plants commonly used in rock gardens, check out the Georgia R&E Garden's Web site (www.griffin.peachnet.edu/garden/ rockgrdnlist.html).

The last step to creating your rock garden is to cover all the exposed soil with pebbles. This topdressing helps conserve water. And it helps the planted area blend in with its rocky surroundings.