The landscaping at a Mills Properties apartment complex can transport you far from St. Louis. When you stroll through such a property in winter, “it's like walking next to a creek in Colorado,” says project architect Jim Parker of Tulsa, Okla.-based Parker Associates. “There's snow on the boulders, and you can hear the creek.”

Since June 2004, it's the residents of The Boulders at Katy Trail who have been imagining themselves in the Rockies—all year long. Boulders of Arkansas limestone tumble through the aptly named community, creating an intertwined series of lakes, creeks, and fountains, Parker says.

Creating such a rocky world took some dollars. The Chesterfield, Mo.-based Mills spent more than $1 million landscaping the 240-unit, $26 million property, which features more than 3,600 tons of boulders.

Why spend so much time and money on such outdoor features? “It's a competitive market right now, and we want to be thought of as the very top of the market,” says O. Bruce Mills, C E O and chairman of Mills Properties, which owns and manages 5,000 apartments in the St. Louis metro area.

It works: Mills gets some of the highest rents in the suburbs for its highly landscaped properties, which target young professionals, empty-nesters, and other renters willing to pay extra for such amenities. At The Boulders, apartments go from $790 for a 649-square-foot one-bedroom to $1,645 for a three-bedroom, two-bathroom unit with a view. The property, which opened in mid-2004, is 73 percent leased.

WATER WORLD: Mills Properties spent more than $1 million landscaping The Boulders at Katy Trail, which features waterfalls, lakes, and fountains..

STREAMSIDE LIVING: The Boulders at Katy Trail attracts well-heeled suburban renters.