Skip to content
1927 Map of the Arboretum


Former Seasonal Arborist Anthony Lombardo, Gardener Brendan Keegan, and Former Horticulturist Laura Mele help plant 2,500 plugs of butterfly milkweed (Asclepias tuberosa) in a reduced-mowing meadow on Peters Hill, enhancing the value to pollinators.
“It is meaningful to look at our landscape as a sanctuary for the many species that could live here if given the opportunity. It is important to enrich the landscape for as diverse an audience as possible whether that is people or birds or insects or mammals.” – Brendan Keegan, Horticulturist

Urbanization and climate change disrupt the local ecosystems of urban environments. The threat of global change to insect and wildlife populations is compounded by habitat destruction and fragmentation. Declines in pollinators and other insects have adverse effects for the plants in urban areas. While the Arboretum’s mission focuses primarily on the cultivation and protection of woody plants, we also steward 281 acres of local ecosystems and the biodiversity that they support.   

The Arnold Arboretum is a sanctuary for organisms facing the effects of global change in the Boston area. As a human-created garden in an urban environment, we steward a wide variety of diverse habitats. To maintain the health and diversity of these habitats, our horticulture staff augments the Arboretum’s ecosystems with a variety of locally-sourced herbaceous species. Low-impact maintenance regimes and managed meadows encourage the growth of spontaneous native vegetation. 

The installation of nest boxes and other constructed habitats across our landscape help support bird and insect populations. The volunteers of our NestWatch program help us to monitor and understand wildlife activity. A recent research collaboration with Tufts University revealed the presence of six bat species on the Arboretum grounds. Our adaptive pest management strategy focuses on plant and ecosystem health, avoiding pesticides whenever possible. Mulched pathways across our landscape reduce damage to plants and local ecosystems. These and other horticultural strategies focus on understanding and protecting the local ecosystems of our urban environment. 

Promoting Native Biodiversity

Beyond growing trees, we are concerned with encouraging native biodiversity and specifically addressing local insect declines. Promoting native biodiversity increases ecosystem productivity and creates a resilient and beautiful landscape. The areas of our landscape in which we promote native biodiversity have attracted organisms and increased the health of the Arboretum as an urban environment 

In some areas of the landscape we have reduced mowing to encourage the growth of spontaneous vegetation like native perennials and grasses. Our selection of locally-sourced plantings for some of these areas creates healthy herbaceous layers, comprising plants adapted to our area and attractive to a range of pollinators. The plantings in Kent Field meadow, for example, have attracted monarch butterflies, bats, and great horned owls to name a few. 

Our solar pollinator meadow at Weld Hill is the first of its kind in the state of Massachusetts. The meadow comprises dozens of native herbaceous species, sourced and collected from local conservation areas and state parks. These plant communities support a variety of pollinator species living directly below solar panels that generate 30 percent of the electricity used by the Weld Hill Research and Education Building.  

Horticulturist planting small seedlings with trowel
Wildflowers blooming
Herbaceous Layer Committee members collecting plants at Myles Standish State Forest, Plymouth, MA.
Weld Hill Solar Pollinator Meadow
northern blazing star by Doug McGrady
In 2021, we worked with Zoo New England to reintroduce Liatris novae-angliae (northern blazing star), a rare native wildflower species, on the Arboretum’s grounds.
solitary bee habitat
Our staff build nest boxes and selectively leave snags, logs, stumps, and leaf litter across our landscape. These become habitats for wildlife and invertebrates. 
Our horticulturists’ effort to create habitats encourages native wildlife to take home in the Arboretum. This includes Great Horned Owls.
Man checking chickadee box.
The volunteers of our NestWatch program monitor bird habitats and gather information on their nesting behaviors. Brendan Keegan
Hemlock Woolly Adelgid
We have an adaptive pest management strategy. We consider alternative methods to pesticides for pest management. In response to the arrival of hemlock woolly adelgid (seen above), we have planted hemlocks from populations with natural resistance to this destructive pest.
Mulch path near Mendum Street Gate
Our mulch pathways direct and localize foot traffic, reducing accidental damage to root systems. These pathways introduce our visitors to other parts of the Arboretum, increasing accessibility to the collections and landscape. Brendan Keegan