Longwood Gardens to purchase 505-acre du Pont Estate in Delaware

Granogue Reserve, in northern New Castle County, will be preserved as open space with plans for public access, eventually. The property is estimated to be worth $50 million

Longwood Gardens, pictured above, will acquire Granogue Reserve, a longtime du Pont family estate in New Castle County, Delaware. The 505-acre property will be preserved.
Jeff Douglas/PhillyVoice

Longwood Gardens, the botanical preserve in Chester County, has entered an agreement to acquire a 505-acre northern Delaware property that once belonged to the du Pont family. The estate, called Granogue Reserve, will be kept as open space.

The sprawling property near Centreville, New Castle County, is about 5 miles from Longwood Gardens and less than 1 mile from the Pennsylvania-Delaware state line. The News Journal reported Wednesday that the estate is estimated to be worth more than $50 millionIn recent decades, the du Pont family formed Granogue Reserve, LTD., LLC to create a plan that would prevent future development on the site.

Granogue Reserve is one of the largest, privately-owned, open spaces of its kind in the Brandywine River corridor. It has a mix of farmland, forest, pasture and meadow. A colonial revival-style mansion sits on a hilltop with views of the Brandywine Valley. Much of the land is still used to farm for corn, soy, hay and dairy.

The land and century-old mansion belonged to Irénée du Pont Jr., who died in December at 103, and his wife, Barbara, who died in 2021. Irénée du Pont Jr. was the great-great-grandson of Éleuthère Irénée du Pont de Nemours, the founder of DuPont Co., and the nephew of Pierre S. du Pont, who opened Longwood Gardens to the public.

Discussions about Longwood Gardens, which is in East Marlborough Township, Chester County, becoming the steward of the Granogue Reserve began in 2016. The Conservation Fund, a national nonprofit, helped survey the site and develop a master plan to maintain the property's pastoral beauty. 

There are no immediate plans to make the Granogue Reserve open to the public, but Longwood officials told the News Journal their goal is to eventually welcome a level of visitation that still allows for the estate to be preserved.

Longwood Gardens has a deep-rooted relationship with the du Pont family. In 1906, industrialist Pierre S. du Pont purchased Longwood's original, 202-acre arboretum, near Kennett Square, to save the historic trees from being felled for lumber.

The Longwood Foundation went on to expand the surrounding land into an 1,100-acre botanical garden — the most-visited, paid public garden in the United States. Longwood is now in the process of a $250 million transformation that will feature several new buildings and exhibits. Its Main Garden Fountain, renovated in 2016, has become a year-round spectacle for visitors dazzled by its themed light shows.

Longwood Gardens president and CEO Paul B. Redman said the purchase of the Granogue Reserve is meant to honor the legacy of conservation that began with du Pont's commitment to the original arboretum.

"We understand the important role this iconic landscape plays in our region's ecology, community and quality of life, and we look forward to working with our partners to ensure this treasure is stewarded for future generations to enjoy," Redman said. 

Grace Engbring, the daughter of Irénée and Barbara, said her parents' intention was to keep the Granogue Reserve a bucolic site for people to enjoy. Over the years, the du Ponts often put on fireworks displays for the public to view at the estate and hosted events for local organizations.

"My father was committed to keeping Granogue as open space to be enjoyed by many and he did this very gracefully just as Longwood will continue to do," Engbring said.

The official ownership transfer of the land could take up to a year. Longwood Gardens has not revealed any conceptual plans for possible attractions or what future visitation of the Granogue Reserve will look like for the public at this time.

The preservation of the estate will be aided by money from a permanent du Pont family endowment and additional support from the Mt. Cuba Center and the Longwood Foundation.