Pittsburgh — Fallingwater is Frank Lloyd Wright's architectural symbol of man living in harmony with nature. But now it seems nature is on the attack.
One of the architect's most prized buildings is surrounded by a discordant landscape dominated by invasive exotic plant species.
Such plants as English ivy and honeysuckle, which are not native to the area, grow nearly unimpeded in the Bear Run Nature Reserve, as the land around the house is called. Unencumbered by natural enemies, the exotic plants strangle trees and threaten to wipe out the native vegetation, according to the Western Pennsylvania Conservancy, which oversees the building.
"We had been invaded and hadn't even realized it," said Cara Armstrong, Fallingwater's curator of buildings and collections.
Later this month, the conservancy will lead a volunteer effort to rip out the invasive exotic plant species and replace them with native ferns, trees, shrubs and other plants.
When Wright designed Fallingwater in 1935 for Pittsburgh department store magnate Edgar Kaufmann Sr. and his family, he placed the home on top of Bear Run, a mountain stream and one of the family's favorite picnicking destinations. The land around the stream wasn't in pristine condition in the 1930s. The original forest had been cleared for logging and agriculture, so the Kaufmanns planted 5,000 tree seedlings when they took possession of the land, said Richard Liberto, a horticulturist and Fallingwater volunteer.
The Kaufmanns' gardeners also used exotic species such as burning bush and wisteria in Fallingwater's landscape.
"Friends would tell the Kaufmanns that it was the most beautiful valley that God never created," Armstrong said.
Eventually, the nonnative plants grew beyond the gardens' borders and into wooded area around Fallingwater.
In one 200-feet-by-15-feet section near Fallingwater's main house and guest house, English ivy forms a solid blanket, stopping tree saplings and other small plants from growing. The established trees seem to be safe, but the ivy is growing up their trunks, Liberto said.
The conservancy is considering the environmental impact of its work -- scheduled for Saturday. The volunteers won't be using herbicides; they will pull the plants up by their roots and repeatedly prune problem vegetation.
"The most you can hope for is to manage the plants, not eradicate them," Liberto said.
Immediately after volunteers pull up nonnative plants, they'll replace them with plants native to western Pennsylvania such as common witch hazel, cinnamon ferns and plantainleaf sedge.
Armstrong, Liberto and Fallingwater director Lynda Waggoner selected the native vegetation by taking hikes and taking cues from the other plants that exist in the area, about 40 miles southeast of Pittsburgh.
If Fallingwater successfully plants a native forest garden, it may inspire visitors to do the same in their own yards, Armstrong said.
"Native is beautiful," she said. "We don't have to be reaching out for exotic plants for some excitement in our lives."
Fallingwater was built for the Kaufmanns as their mountain retreat. Its nearly four-year construction was completed in 1939. The couple used it until Edgar Kaufmann Sr.'s death in 1955 and Liliane S. Kaufmann's death in 1952. Edgar Kaufmann Jr., the Kaufmanns' only child, inherited Fallingwater in 1955 and used it as a retreat until 1963. He donated the building and hundreds of acres to the Western Pennsylvania Conservancy, which opened it to the public in 1964.