Harriet Pattison, a noted landscape architect whose projects included the Kimbell Art Museum in Fort Worth and the memorial to Franklin D. Roosevelt on Roosevelt Island in New York City, both of them collaborations with the architect Louis Kahn, with whom she had a son,died on Wednesday at her home in Newtown Square, Pa. She was 94.
The death was announced by the son, the filmmaker Nathaniel Kahn, her sole survivor.
Ms. Pattison’s biggest contribution to landscape architecture may be her work on the Kimbell site. In a 2015 oral history interview with Charles Birnbaum, the president of the Cultural Landscape Foundation, she said it had been her idea to grade the site in a sloping way so that the building looked like “it really belonged there, and it wasn’t sitting on a plinth, which had been Lou’s approach.” She also adjusted a water feature there so that instead of it being a “big, sort of dull reflecting pool,” water spilled from one pool to another.
“The sound of it was to be a part of the whole poetry of the building,” she said.
“I brought a sense of nature, and of the site, to Lou’s work,” Ms. Pattison said in “My Architect,” a 2003 documentary film by Nathaniel Kahn about his father.
The Roosevelt memorial, at the southern tip of Roosevelt Island in the East River, was commissioned in 1973. Mr. Kahn envisioned it not as a building but as a landscape — a triangular lawn pointing to a roofless outdoor chamber. Ms. Pattison worked with Mr. Kahn on many variations of the design to stay on budget and satisfy funders.
William Whitaker, the curator of the Architectural Archives of the University of Pennsylvania, which holds papers that had been left in Mr. Kahn’s office when he died in 1974, studied multiple drawings by Mr. Kahn and Ms. Pattison, and what he saw convinced him that she had had a significant hand in Mr. Kahn’s final design.
After Mr. Kahn’s death, at 73, the project was mothballed. It was revived more than 30 years later, and adjustments to the design were made by a New York architecture firm, Mitchell/Giurgola Architects. Ms. Pattison said she was not consulted. The firm’s landscape architect told The Pennsylvania Gazette, the alumni magazine of the University of Pennsylvania, “I never heard the name Harriet mentioned.”
Ms. Pattison practiced landscape architecture for more than 30 years, working alone but often collaborating with architects she knew through Mr. Kahn. Her notable projects included a master plan for the Hershey Company’s 150-acre Pennsylvania headquarters, with the design firm Ballinger; the design for the Columbia Avenue Station in North Philadelphia, with Mitchell/Giurgola; and landscapes for private homes in Pennsylvania and Maine, including several designed by Peter Bohlin, an American Institute of Architects gold medal winner.
A show of her work was presented at the University of Pennsylvania in 2016. That year she was named a fellow of the American Society of Landscape Architects. Mr. Birnbaum told the New York magazine site Curbed that in all of Ms. Pattison’s projects “you see the hand of an artist.”
Hers was a complicated life. As her son’s film “My Architect” tells the story, she carried on her romance with Mr. Kahn, who was nearly 28 years her senior, while he was married to another woman. And for many years, while she raised her son and tried to establish herself as a landscape architect, she all but hid herself a way.
“I was with a man I loved; I had a child I adored and a path toward a career,” she wrote in a memoir, published in 2020. “But these had cost me the acceptance of ‘society.’ I felt caught between two eras, and even two parts of myself.”
Ms. Pattison never married, and she lived alone until her death.
To viewers of Mr. Kahn’s film, she may have seemed to have sacrificed everything for a man she couldn’t marry. By contrast, her book, “Our Days Are Like Full Years: A Memoir With Letters From Louis Kahn,” portrays her as a woman who built a career and a family despite great challenges.
The book includes hundreds of letters, telegrams and postcards that Ms. Pattison received from Mr. Kahn in the 15 years before his death. The letters are intimate, revealing and self-deprecating; one, sent from Pakistan on March 31, 1965, begins: “Sweetie, The conquering hero has conquered nothing.” They often included sketches of buildings or drawings of imaginary animals for young Nathaniel. Some document their professional collaborations.
“We were soul mates and inspired each other,” Ms. Pattison said in her son’s film. “It was an equal exchange in many ways.”
Harriet Pattison was born on Oct, 29, 1928, in Chicago, the youngest of seven children of William Lawrence Pattison, who ran a small real estate company, and Bonnie Abbott Pattison. Harriet attended the private Francis Parker School in Chicago, spent three semesters at Wellesley and then transferred to the University of Chicago, from which she graduated. Deciding to become a set designer, she enrolled at the Yale School of Drama.
In her memoir, Ms. Pattison wrote that she and her four sisters were not given middle names. Their parents, she said, expected them to “complete” their names by marrying.
Ms. Pattison’s first encounter with Mr. Kahn, in 1953, was fleeting: She was a Yale drama student, and he was overseeing construction of the Yale University Art Gallery. “I didn’t know who he was,” she recalled in the oral history, “But that night, I wrote down that I had met an amazing man. And that was it.”
She studied moral philosophy in Edinburgh for a semester and then moved to Philadelphia to take piano lessons from a friend, Edith Braun, who promised to help her get her life in order. Nearing 30, “I was still searching, at that late age, for some way of expressing myself in the arts,” Ms. Pattison told Mr. Birnbaum in the oral history interview.
In 1958, soon after moving to Philadelphia, she was formally introduced to Mr. Kahn at a holiday party. That led to what were “the most important 15 years, I think, in Lou’s life and in mine,” she told the journalist Martin Pedersen in the online magazine Common Edge in 2021.
When Nathaniel was born she was 34 and had not yet chosen a career. Landscape design seemed like a good fit. But in the mid-1960s, she wrote in her memoir, “a woman with a child and no wedding ring was cause for gossip, even suspicion.”
“I hoped I could maintain a quiet anonymity,” she added, “but I soon found myself developing a kind of affectless outer shell to protect myself.”
Mr. Kahn arranged for her to work for Dan Kiley, a prominent landscape architect in Vermont. Mr. Kiley’s studio was a haven for mother and son, “a kind of utopia, an openhearted commune focused on a single artist’s work,” she wrote.
Yet observing the hierarchy in Mr. Kiley’s firm, she decided that to succeed as a landscape architect she needed a professional degree. She enrolled at the University of Pennsylvania.
After graduating, Ms. Pattison went to work for George Erwin Patton, a landscape architect who often collaborated with Mr. Kahn. Mr. Patton assigned her the Kimbell Museum project, which gave the couple an opportunity to work together.
But there were obstacles to their relationship. Mr. Kahn had a daughter, Sue Ann Kahn (today a noted flutist) with his wife, Esther Kahn, and another daughter, Alexandra Tyng (who became an artist), with Anne Tyng, an architect who worked in his office. That meant juggling three families while running a firm, teaching at the University of Pennsylvania and making frequent trips to India, Israel and other places where he had or hoped to have commissions.
Mr. Kahn visited Ms. Pattison and Nathaniel when he could. “Lou would call at the last minute and say he was on his way,” Nathaniel said in his film. “My mother would frantically whip up a five-course meal and have a martini waiting in a frozen glass.”
In 1974, Mr. Kahn promised to leave his wife, according to Ms. Pattison. As she recalled in her son’s film: “I said, ‘I can’t bear it any longer. You have to live with us.’ And he said he would.”
Then Mr. Kahn left for Ahmedabad, India, where the Indian Institute of Management, which he had designed, was under construction. A week later, his body was found in a men’s room at Pennsylvania Station in New York, where he was to catch a train back home to Philadelphia. He had had a heart attack.
Nathaniel Kahn’s movie, an Oscar nominee, helped burnish Louis Kahn’s reputation as an architect but did nothing for his reputation as a husband and father. After its release, Kahn biographers often “took a dim view of his domestic life,” Ms. Pattison told Mr. Pedersen. “That annoyed me because they took sides and were judgmental.”
Her annoyance led her to write her memoir, she said. In it, she described the dedication ceremony for the F.D.R. memorial, in 2012, during which she was introduced by Tom Brokaw as having “worked closely with Louis Kahn to develop the magnificent landscape for this park.”
The acknowledgment “thrilled and surprised” her, she wrote, adding, “My great longing was to live a life in art, and with Lou’s help I had found a way to do it.”