With its soothing dark walls and shady mesquite trees, the enclosed patio shown here would be a pleasant spot even without water. But the addition of a water lily-filled pond turns the space into a genuine oasis.

Landscape designer Michelle Hearon and architect Diana Osborne designed the patio as a restful retreat at Osborne's home in Tucson. The pond is an irregularly shaped cement basin, roughly 9 feet in diameter, set into flagstone paving and generously embellished with hefty boulders from the nearby Catalina Mountains.

One particularly dramatic stone with a crevice was turned into a water feature. Osborne drilled a hole through the top of the stone, inserted flexible tubing, and attached the tubing to a recirculating pump. The pump releases a slow, steady trickle down the crevice, creating the illusion of water seeping from a natural spring.

The pond is planted with cattails, dwarf papyrus, water irises, and water lilies and is stocked with goldfish and koi. Except for needing the vegetation thinned occasionally, the pond takes care of itself. "I don't feed the fish or the plants," says Osborne. "The fish eat the algae, and they provide the fertilizer for the plants."