The NPS Era (1940-present)
When Frederick died in 1938, Louise's niece, Margaret Van Alen, inherited the estate and put it up for sale. Unfortunately, the depression had put an end to America's 'Gilded Age' and there was no buyers for it. Franklin Roosevelt, by then President of the United States, knew the estate well and did not wish to see it broken up for development. He arranged for Congress to purchase the estate in 1940 and make it part of the National Park Service.
The advent of World War II, a year later, made it very difficult for the NPS to maintain the estate. While the mansion and main grounds were kept going, lack of manpower and money led to a general decline in the gardens. They became overgrown with weeds and brush and the grape vines (some 6 inches in diameter) began to destroy the arbors. Eventually, the entire area was declared to be hazardous and was fenced off. In 1950, a windstorm heavily damaged the greenhouses, and they were eventually torn down.
The gardens remained generally forgotten for over 30 years. In the late 1960's, the NPS began to document their ruins. However, it wasn't until a decade later that they received a grant from the Preservation, Restoration and Improvement Program to help partially restore them.
The brick walls were painstakingly restored to match the originals. The mortar was especially difficult to match, as it had a distinctive pink hue. It had to be chemically analyzed to match the composition and consistency, but they could not come up with the right color. Then, someone discovered that by crushing a few bricks into the mix, the mortar came out the right shade of pink.
The restoration of the walls was completed in 1983. At the same time, the drainage system was restored as well as the main arbors at the Reflecting Pool and Loggia. The workers rebuilt them from the original, historic plans out of cypress wood.
Unfortunately, that was the extent of the money received in the grant. There was nothing left to actually replant the garden beds.