Sayen Park Botanical Garden (30 acres), also known as Sayen House and Gardens, is a municipal park and botanical garden located at 155 Hughes Drive, Hamilton Square, an area within Hamilton Township, New Jersey. The garden is open year-round from dawn to dusk without charge, though at its peak in the spring.
The garden began in 1912 when Frederick Sayen purchased the site with his wife, Anne Mellon Sayen, a daughter of the prominent Mellon family. The Sayens built a "bungalow" home in the Arts and Crafts style, though with Victorian interior design, and surrounded it with plants and flowers acquired during world travels. The principal collections include species from China, Japan, and England.
The Sayen site became municipal property in 1988, when Hamilton Township purchased the site from developer David Cellars. The park was opened to the public in 1991. The township expanded and improved the park in 2003. Today the garden contains more than 1,000 azaleas, nearly 500 rhododendrons, and more than 250,000 flowering bulbs for spring display, as well as ponds, bridges, gazebos, and walking trails.