During the American Civil War, the demand for Hawaii sugar grew, but Widemann supported the Confederate States.

[3]: 180 After leasing Grove Farm to its manager George Norton Wilcox (1839–1933) in November 1864,[4] Widemann moved to Honolulu to work in the capital as a supreme court judge.

Wilcox had an irrigation system built to bring water from the wet mountains to the flatter lower elevations where the crops were grown.

In 1903 the family hired Charles William Dickey to design a house for Ralph Wilcox and his wife Daisy Rice.

Dickey also supervised a renovation of the main house in 1915 which removed interior walls to create large open spaces.

By 1974, sugar production was leased to Alexander & Baldwin, while the company moved into residential and resort real estate operations.

[4] The Wilcox estate was added to the National Register of Historic Places listings in Hawaii on June 25, 1974, as site 74000722.

The 2 ft 6 in (762 mm) narrow gauge[9] Grove Farm Company Locomotives[10] were stored in a warehouse just to the west in the area known as Puhi, also listed on the NRHP, and formerly owned by Mabel Wilcox.