Wilbur Sisson returned to Rosendale after his retirement in 1918 and began growing peony plants in his sister's backyard. His enthusiasm for the business resulted in subsequent expansion and the gradual development of an important commercial enterprise that has had a lasting impact on the village of Rosendale and its inhabitants. At its peak, Sisson's Peony Gardens occupied a four-acre interlocking series of gardens that wound throughout the village and brought thousands of visitors to its annual June Peony Festival. Sisson began his mail-order sales of roots and plants from his sister's home in the early 1920s, shipping throughout the United States and beyond, while developing local nursery acreage with the help of partners Wilbur Lawson and later Jesse Phillips, who inherited the business on Sisson's death in 1950.

Today, the Windmill Garden is the last surviving remnant of this once busy and vibrant nursery. Purchased by Sisson in 1928, this long narrow lot, immediately to the south of his original "Home Garden," became the main entrance to the complex of gardens, with its long beds filled with masses of colorful scented peony plants. The entrance gate opens into the garden from Main Street, with a path leading directly to the windmill after which the garden was named. Both structures were designed and built for Sisson by his new assistant, Jesse Phillips, in 1928, and are unchanged to this day. Their rustic style is accentuated by the use of local fieldstone, taken from the foundation of a local church when it was rebuilt. The windmill with its bright blue sails, clearly seen from Main Street, became Sisson's signature and was used extensively for advertising purposes, as well as being the registration site for entrance into the garden.

In 2005, the Rosendale Historical Society purchased the garden; they are in the process of restoring the original peony beds. This site will be open seasonally as a peony display area to commemorate the contribution that Wilbur Sisson and Jesse Phillips made to the community of Rosendale.