Planting Fields Arboretum State Historic Park is a large garden in Long Island, New York. It covers 409 acres and started in 1913. Businessman William Robertson Coe and his wife, Mai Rogers Coe, bought the land to build a peaceful home. The estate, called Coe Hall, has a big mansion and special gardens made by famous designers. After the first designer passed away, the Olmsted Brothers continued the work. The park is important because it has kept its original look, while many other estates were changed into golf courses or houses. A new book was released that gives more comprehensive details about the park. It includes photos, drawings, and writings from professionals.

The park is now changing to help nature. A revitalization project is ongoing to improve biodiversity by planting more local plants. Oak trees were planted to replace old European beech trees, as they are better for the environment. Meadows are now cut only once or twice a year to help animals and insects live there. A new garden will also be made by Piet Oudolf, a renowned designer from the Netherlands. This park is the biggest living commission by the Olmsted Brothers, which makes it exceptional in the country. The stewardship team said they hope people can see how important it is to care for both history and nature.