Lassig was born in 1938 and loved flower gardens even as a young child. One day he went missing and his worried family found him lying in a flowerbed talking to the flowers. He often visited the Church’s greenhouses because he loved to watch the preparations. One day he accompanied his father to the greenhouse and watched the head landscape architect work. He asked the man—Irvin T. Nelson—if he was the head gardener. They talked about the work for several minutes until his father urged him to get to the point. Lassig was hesitant, so his father said, “This boy wants to work for you with the idea of taking over.” Lassig assured Nelson he could stay until he was ready to retire. At the age of fifteen, Lassig began working seasonally for Nelson pulling weeds and then later planting.
He served as a missionary to Japan and then on a labor mission tending for the gardens at the Mormon pavilion at the New York World’s Fair in 1965 and 1966. He earned a bachelor’s degree in horticulture and botany from Brigham Young University in 1967. He went to Seattle, Washington, one winter to work in landscaping and learn about landscape lighting techniques, which later became an essential skill for Christmas lighting on Temple Square.
Nelson called him one day and said, “Do you remember what you said when you first came to work for me?” Nelson then told Lassig that he always thought that Lassig would replace him someday. Nelson was now in his seventies and President David O. McKay had asked him to find someone to be his protégé. Nelson told Lassig that he had told President McKay he already had someone in mind. Part of Lassig’s preparation for that role was to obtain a master’s degree from Utah State University. When he graduated in 1972, Nelson retired and Lassig took over the post.
He and his wife Sylvia had eight children. After she died in 1991, he married Janet McMaster who had five grown children. Lassig died on October 25, 2015. He had retired a few years prior to his passing.