The Park Hill nursery is located about one hour southeast of Tulsa, Oklahoma. and home to the Greenleaf corporate office. In an area of Oklahoma deemed "Green Country," the nursery was planted among the rolling hills, Illinois River and Lake Tenkiller in 1945 and has grown to over 600 acres of container-grown crops and an extensive propagation facility. The corporate office at the Park Hill nursery was designed by, and built as a home for, John Nickel and his family. Construction began in October 1965 and was completed in the summer of 1966. The original plans for the home were designed to allow for conversion to office space without having to renovate the entire structure. The conversion to office space took place in June 1969. In 1986, the office space was expanded an additional 4,200 square feet. During that same year, the landscaping around the office was completely redesigned. The plantings represent examples of ways plant material can be used in contemporary landscapes. Presently, during the peak of the season, the Park Hill operation employs 650 people and produces over 10,000,000 liners and 6,000,000 finished plants. Of these, there are 58 varieties of conifers, 901 varieties of broadleaf evergreens, deciduous shrubs and color, and 170 varieties of shade and flowering trees.
The nursery is on Highway 82, just 9 miles south of Highway 62.