The abandoned site that became the Mount Washington Arboretum in 1999 also served for a time as a nursery for the work of the Mount Washington Preservation Trust. This part of the Arboretum continues to function as a nursery, growing and trying out various trees, shrubs, and perennials that might be used in the Arboretum or elsewhere in the neighborhood. It can also be used to rehabilitate trees that suffer from disease or need special attention, and it has its own irrigation system because plants in pots tend to dry out quickly.