In 1851, he emigrated to the US preceded by his brother, also a horticulturalist, who had emigrated in 1849, to work for noted landscape architect
Andrew Jackson Downing. From 1851 to 1853, he was responsible along with
William Dunlop Brackenridge for improving the
National Mall,
Lafayette Square, and the
Smithsonian Museum grounds. In 1852, he started a seed business. In 1854, Saul became the first Chairman of Washington’s Parks commission, the forerunner of the Park and Planning Commission for the city. In 1854, he purchased his first nursery and in 1872, he purchased his second. He operated twenty greenhouses using his horticultural skills to create numerous new varieties of plants. He was a member of the American Society of Florists and was a frequent contributor to the journal
The Horticulturalist. ==Personal life and death==