With the landscape architect James van Sweden, Mr. Oehme (pronounced UR-ma) forged an unlikely partnership that became the Washington-based firm Oehme, van Sweden & Associates. The alliance began in earnest obscurity in the 1970s: They planted their own designs from the back of a pair of Volkswagen Squarebacks.
When a Federal Reserve Board member asked them to redesign the Fed’s Virginia Avenue NW gardens in the 1970s, the resulting two-acre confection of fountain grass, Autumn Joy sedum and feather reed grass showed the world an alternative to the old city park model of foundation evergreens bordered by ivy ground cover.
A slew of public and private commissions followed, other designers aped the style and nurseries had to grow and sell the Oehme-van Sweden plant palette to keep up with demand.
In addition to various grasses, the team popularized such perennials as black-eyed Susans, coneflowers, joe-pye weed, salvias and Russian sage.
With artful promotion, they called their style “the New American Garden” and said their gardens served as a metaphor for the American prairie.
In addition to designing gardens for adventurous and well-heeled clients, the firm also shaped prominent public spaces in the Washington area, including Reagan National Airport, the National World War II Memorial and Freedom Plaza.
Their champion at the Federal Reserve, David Lilly, wrote that the garden there evoked imagery that moved “away from the aristocratic European model” toward a more egalitarian “Great Plains heritage.”
The gardens were also rooted in Mr. Oehme’s Germanic passion for improved varieties of grasses and perennials planted as they might look in nature — carefully grouped and en masse. Mr. Oehme loved that his gardens attracted birds, bees, butterflies, dragonflies and frogs, but his plants were not native to one land or region. Mr. Oehme was looking for effect, not ecology.
A major influence was Karl Foerster, a plant breeder and writer active before World War II who emphasized the natural and dynamic seasonal aspects of herbaceous gardening.
Throughout his life, Mr. Oehme returned to a saying of Foerster’s: that grasses “were the hair of the Earth.”
Wolfgang Walter Oehme was born in Chemnitz, Germany, on May 18, 1930. He began growing plants when he was 5, in a corner of his parents’ community garden plot.
He moved north with his family to Bitterfeld in 1943 when his father was transferred to the city as a policeman during World War II. The city later became part of East Germany under Soviet control.
Mr. Oehme apprenticed at 17 at a Bitterfeld nursery, where he learned plants, propagation and planting techniques. He later moved to the city parks department, where a mentor introduced him to the ideas of Foerster and encouraged him to become a landscape designer.