The Arboretum becomes a riot of color in October, with leaves turning deep red, fiery orange, and bright yellow. Have you ever wondered why this happens every autumn? Outdoor Educator Ana Maria Caballero will take us through the science of fall leaf color, including an exploration of pigments and abscission, a hands-on experiment to reveal the array of pigments present in every leaf, and a walk in the landscape to take a closer look at leaves in all phases of color change.

Join docent Paul Eldrenkamp for a visit to five groups of trees that each played a particularly significant role in shaping five very different civilizations: Eastern White Pine, Cedar of Lebanon, Western Red Cedar, Oaks, and the five sacred trees of the Kiso Forest in Japan.

As we approach the end of the growing season, it’s time to start thinking about next year’s plantings! What trees or shrubs should you plant in your own yard? Which plants will fare best in your particular space and microclimate? Join Horticulturist Rowan Payne-Meyer for a class on garden design for woody plants. We will begin in the Hunnewell Lecture Hall for a discussion on garden design techniques, and then move outdoors to see the design strategies used in the Leventritt Shrub and Vine Garden and the Bradley Rosaceous Collection.

Smithsonian Trees of North America is a new, beautifully illustrated guide to more than 325 common trees on this continent. Join author John Kress for a book talk on this indispensable new guide, complete with hundreds of range maps illustrating where the trees can be found; thousands of photographs of the trees’ leaves, bark, flowers, and fruit; in-depth studies of the trees’ biology, ecology, and evolution; and fascinating discussions of the trees’ future in a world of rapid environmental change. And keep an eye out for several photos taken by our very own Ned Friedman!

This is a virtual talk held over Zoom.

We know that trees are a key ally in the fight against climate change and urban heat islands, but not every tree works in every situation. Selecting the right tree for your yard or landscape is critical both for the health of the tree and for the strength of the ecosystem services they provide. Botanist and researcher Henrik Sjöman’s new book, “The Essential Tree Selection Guide,” is a valuable new tool for making these tree selection decisions: an A to Z guide of over 550 trees, the book comes complete with explanations of each tree’s ecosystem benefits, its resilience to drought and storms, and key considerations for site placement. Join us on December 8 for a virtual book talk on this invaluable new guide.

Author Henrik Sjöman is Senior Researcher at the Swedish University of Agricultural Sciences, Scientific Curator at Gothenburg Botanical Garden, and Honorary Research Associate at Kew Gardens.

Accessibility: This program is held virtually.

Audience: This program is geared towards adults.

Frederick Law Olmsted, considered the father of landscape architecture, designed some 500 public spaces in North America. The Arnold Arboretum is the only arboretum he designed, a National Historic Landmark, and a model for others around the world. Docent Bill Beizer, will identify the elements of the Arboretum that best reflect Olmsted's philosophy and approach to landscape design.

Start your 2025 year list off on this easy 90-minute walk from the main gate to the ponds and back. In addition to looking for winter birds we will admire the Arboretum's impressive woody plant collection.

The Arnold Arboretum has an over 150 year legacy of preserving native and exotic species in an ever changing global environment. This one hour tour will highlight some of the Arboretum's successes with endangered historic trees, current initiatives to preserve threatened species among its collection of some 16,000 woody trees, shrubs and plants, and the work the Arboretum has underway to meet future challenges from climate and habitat loss.

When gardens go dormant for the winter months, there are still certain species and cultivars that draw the eye with their bright berries, interesting seed pods, and spectacular bark. Join Warren Leach for a book talk on his new book, "Plants for the Winter Garden: Perennials, Grasses, Shrubs, and Trees to Add Interest in the Cold and Snow," and discover all that a winter garden has to offer. Warren Leach has years of gardening experience in the cold Northeast and will be sharing all of his winter garden tips, from plant selection and placement, to pruning techniques, to structural components that complement the plants themselves. And if you decide to buy a book after the program, make sure to look for some references to the Arnold Arboretum's own winter landscape!