Although Saugus Iron Works National Historic Site contains numerous species of native plants, animals, and other organisms, non-native species can be easily seen within the historic site. Many of the non-native species at Saugus Iron Works are classified as plants.
In 1996 and 1997, a plant inventory was conducted by the Brooklyn Botanic Garden to determine the plant diversity within the historic site. One hundred and sixty species of plants were identified within Saugus Iron Works. Of these 160 plant species, 59 are non-native and 11 of these 59 species are considered non-native and invasive.
Many species, such as the plants found in the Iron Works House 17th century herb garden, are considered non-native, because these plants are originally from Europe or Asia. However, these herbs are not classified as invasive, because they do not outcompete native plants for sunlight, water, nutrients, and habitat within Saugus Iron Works. Other non-native plant species, such as Norway maple (Acer platanoides) and common reed (Phragmites australis) are considered non-native and invasive because these plants are able to outcompete native plants. As non-native invasive plants continue to outcompete native ones, the populations and species of native plants start to decline.
In 2003, National Park Service staff conducted a survey of Norway maple, common reed, and other non-native invasive plants within the historic site. The primary goals of this survey were to identify which invasive plant species inhabit the site, determine the population densities of the invasive plant species, and map where the invasive plant species occur within the historic site. The survey identified and mapped 11 primary invasive plant species and listed an additional 31 secondary exotic plant species within Saugus Iron Works. This survey is currently being used by park staff to control and monitor the 11 primary non-native invasive plant species. This survey report may be downloaded in the "Related Information" section below.