James van Sweden, FASLA, the landscape architect and author who transformed the texture of American public spaces and gardens over four decades, died September 20 at his home in Washington, D.C., after a long illness. He was 78.

Van Sweden and his partner, Wolfgang Oehme, founded their firm, Oehme, van Sweden & Associates, in Washington in 1975. With an evangelical zeal, and aided by Oehme’s expert horticulture, van Sweden unleashed an explosion of romantic naturalism in landscapes large and small, offering torrents of grasses and huge wildflowers as an alternative to perfunctory public plantings and lawns. Nationwide, and especially around Washington, he composed public gardens, parks, memorials, and campuses to be engrossing in all seasons, unbound in form and flush with colors before browning toward collapse and a startlingly rich afterlife. The firm’s many residential projects range in scale from sweeping meadows and marshy waterfronts to intimate woodland gardens and lush little terraces around pools. Legions of designers and home gardeners embraced the firm’s style, which became known as the New American Garden. In its composed wildness, the approach drew new eyes to overlooked spaces and showed people in suburbs and cities a multitude of ways to live more comfortably with nature nearby.

Van Sweden’s books, among them The Artful Garden: Creative Inspiration for Landscape Design, Gardening with Nature, and Architecture in the Garden, sold remarkably well to broad audiences. He received the ASLA Design Medal in 2010, and was also honored, alongside Oehme, in 1992 with the American Horticultural Society’s Landscape Design Award. Oehme died in December 2011. The Oehme, van Sweden firm continues to operate under the founders’ partners, Sheila Brady, FASLA; Lisa Delplace, ASLA; and Eric Groft, ASLA. Van Sweden is survived by two sisters, Karyl Mangus, of Grand Rapids, Michigan; and Christie Kauffman, of Camp Hill, Pennsylvania.

The Cultural Landscape Foundation has a biographical profile and an extensive oral history of van Sweden on its website. A feature about van Sweden and the redesign of his own garden on the Chesapeake Bay appeared in LAM in January 2012.