1943 - 2025
Jan was born on December 2, 1943, in Brits, South Africa, the youngest of eleven children born to Barend Christoffel Potgieter and Cornelia Jacoba Vreugdenburg. He completed high school in Pretoria and served one year in the South African Defense Force.
A lifelong learner with a curious and thoughtful mind, Jan pursued many areas of study throughout his life, including theological coursework with the Lutherans. Though as a committed Calvinist, he chose not to graduate from that program. His professional calling, however, was clear—he became a respected landscape architect. Known professionally as Jan Plant, he owned a successful business designing gardens across South Africa for mining corporations and also operated his own nursery.
After relocating to the United States, Jan continued to share his gifts, designing gardens for distinguished clients. Even later in life, he remained active and devoted to his craft, lovingly maintaining the rose garden at Shining Rock Golf Club and working in the greenhouse at Koopmans Lumber.
On April 16, 1965, Jan married the love of his life, Susanna Lesia Aletta Kruger, affectionately known as Pattie. Their marriage was one of deep devotion and partnership until her passing on November 19, 2018.
Following Pattie’s death, Jan moved to the United States to live with his daughter and son-in-law. During this time, he formed a cherished companionship with his dear and special friend, Laurie Martin, who loved calling him “My Jan.” Together they shared meals, laughter, and countless hours of thoughtful Bible discussion—moments they deeply treasured.
Known affectionately as “Oupa Jan” to friends and “Koen” to family, Jan had a rare gift for connection. He saw every stranger as a future friend. In Bethal, South Africa, he was affectionately regarded as the unofficial mayor, known for his warmth, generosity, and open heart. His kindness was often quiet and unseen—he paid college tuition for multiple young people who never knew their benefactor.
Within his church family, Jan was known for his generosity and humility. His hand was always open to those in need, and he lived his faith through action. Jan loved to travel—especially by train—and frequently visited Chicago and Florida, where he spent time with his beloved niece, Uda, whom he called “the chosen one.”
Jan also had a legendary love for food, particularly dessert. He always ate dessert first, explaining that life was unpredictable and it was best to begin with sweetness.
Above all else, Jan lived by faith. He walked by faith in Christ alone, knowing himself to be a child of God and often referring to himself, with humor and humility, as a stubborn old “Dutchman.” His faith was steady, simple, and deeply Christ-centered.
Jan was preceded in death by his beloved wife Pattie, his parents, and all ten of his siblings. He was the last great tree to fall on both sides of his and his wife’s families.
He is survived by his only daughter, Maria Magdalena Steinmann; his son-in-law, Frederick Carel (Ferdi) Steinmann; his two grandsons, Iwan Carl Steinmann and Marcu Frederich Steinmann; and his special lady friend, Laurie Martin.
Family and friends are invited to gather Friday, December 19, 2025, starting at 2:00 p.m. at the Buma-Sargeant Funeral Home, 42 Congress Street, Milford, followed by a Memorial Service from 3:00–4:00 p.m. Private interment will follow.
IN LIEU OF FLOWERS, MEMORIAL CONTRIBUTIONS MAY BE MADE TO THE MENDON COMMUNITY CHURCH BUILDING FUND, 4 HARRINGTON STREET, MENDON, MA 01757.
