WELCOME TO THE JUNGLE Bruce Wakefield (left) and Jerry Grossnickle impart a tropical look to their upper terrace with bold-foliage specimens such as a giant-leafed rice paper plant.

"THESE WERE SUPPOSED TO BE PURPLE," Jerry Grossnickle confesses, pointing to a cluster of cream-colored lilies and smiling almost ruefully. On an overcast, late-summer afternoon, the myriad flowers in his garden—a lush two acres along NW Old Germantown Road about a mile west of Forest Park—take on an almost preternatural brilliance. Grossnickle’s longtime partner, Bruce Wakefield, reaches for one of the blooms, which is almost as pale as his spotless oxford. The colors of lilies vary according to weather and age, Wakefield points out; maybe they’ll bloom the right shade of rich lavender next year.

In that sense, the lilies are a work in progress, as is the garden itself—a spectacular, steeply sloping expanse that Grossnickle, a 60-year-old lawyer, and Wakefield, a 54-year-old accountant, designed, planted, and continue to maintain themselves. And despite a few failed experiments, this horticultural labor of love is a brilliant piece of landscape design and a testament to the patient art of collecting and raising exotic plant specimens from around the world.

garden forest yard

BUILDING BLOCKS Broad-leafed ornamental rhubarb and the budding heads of sedum (foreground) lend structure to billowing beds of summer blooms.

Following the curve of a stream that runs intermittently along the cooler eastern side of the property, Grossnickle leads the way down the hill, away from the two-level house overlooking the site, which the couple built in 1990. A narrow green swath of lawn, flanked by mixed borders of shrubs and perennials, sweeps down to the base of the incline, where fat, glistening koi trace lazy circles in the shallows of a hand-dug pond.

“This slope is one of the reasons we bought the property,” Grossnickle says. “We knew that it would make a great garden spot.”

Actually, the lush creation, which Wakefield modestly describes as “a collection that we’ve tried to put into an interesting design,” contains several gardens in one, each reflecting the distinct microclimates of the entire five-acre plot.