Many of the trees were planted, some going back over 100 years, but some grew here naturally. Theodore Wirth, the first Park Superintendent, kept many of these trees, and these remain today. During his tenure, Mr. Wirth planted hundreds of new trees as part of his master design. The property has been transformed from a bucolic country estate to a municipal botanic garden, including many fine trees and shrubs. The Conservancy has developed a tree map, which lists a sampling of the specimens.

Tree species include: shagbark hickory, Katsura (a native of Japan), black birch, golden larch, kousa dogwood, and weeping blue spruce. Over 40 species are highlighted in the tree map. The oldest trees are the oaks. Several of the trees in the park are State Champions, as designated by the Connecticut Botanical Society, notably the mono maple and the golden larch.