Henriette Montgomery

Henriette de Sieyes Montgomery, a devoted environmentalist who headed the board of Group for the South Fork, now known as Group for the East End, for several years in the 1980s and 1990s, died on Sept. 26 at her apartment in Manhattan. She was 93 and had been in declining health.

Mrs. Montgomery and her husband, Robert H. Montgomery Jr., rented houses on the South Fork for years. That was until 1967, her son, Sam, wrote, “when, as Mrs. Montgomery liked to tell it, she made her annual foray to find a new rental and instead, without telling her husband, bought a modest house on Howard Street in Sag Harbor.” The couple later moved to a house on North Haven with a bigger yard. Mrs. Montgomery, who had volunteered and studied landscaping at the New York Botanical Garden in the Bronx, created a garden there that would be featured on a number of East End garden tours. 

As the chairwoman of Group for the South Fork’s board, “she really possessed a combination of grace and strategic thinking that, to me, were the best way to run a board,” said Robert DeLuca, the organization’s president. “She had a vision for where the organization was heading and worked hard with our fellow board members to get us there.” 

She also volunteered with the Sag Harbor Tree Committee. 

Her son recalled that for all his mother’s love of the South Fork’s natural beauties, “she had long overlooked the humble potato field as a feature that made it so stirring.” 

“They are flat and undramatic,” he remembered her saying. “You only realize how beautiful a potato field is when it’s gone.” 

Mrs. Montgomery was born on Sept. 7, 1923, to a French diplomat father, Jacques de Sieyes, and an American mother, Louise Paine, in an 11th-century priory in Le Bourget-du-Lac in the Savoie region of France. She attended the Potomac School in Washington, D.C., the Madeira School in McLean, Va., and then graduated early from Vassar College with the class of 1944-45, after accelerating her studies to serve in the Office of Strategic Services during World War II. 

She and her husband, a lawyer for figures in film, theater, and the arts, were married in the early 1950s. She worked in the education department of the Metropolitan Museum of Art. They split their time between Manhattan and the South Fork. 

Mr. Montgomery died in 2000. She is survived by her son, Sam Montgomery of Los Angeles, a daughter, Margaret Montgomery of Manhattan, and two grandchildren. 

A service will be planned in Sag Harbor at a future date. 

Contributions have been suggested to Group for the East End, P.O. Box 1792, Southold 11971.