For summer vacation, I headed off to Hershey Park in Pennsylvania. While there, I visited the Hershey Gardens, a garden created in 1937 by Milton Hershey (yes, the chocolate guy). The gardens a bit touristy, but overall it has a very large collection of plants, especially the Rose Garden.
In the middle of the gardens, is what they refer to as a Japanese garden. It is not a traditional Japanese garden, but is comprised of many planting that one would find in Japanese gardens. There are few features, other than a Japanese lantern and some assorted stones. There is also a pond and some impressive mature maples that were about 75 years old.
Website: http://www.hersheygardens.org/