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Events for September 20, 2025

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10:00 am

A rainbow of leaves from green to yellow to red

The Science of Fall Leaf Color

September 20, 2025 @ 10:00 am – 12:30 pm
Hunnewell Lecture Hall 125 Arborway, Boston

The Arboretum becomes a riot of color in the fall 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.

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Rooted in history.

The Arnold Arboretum sits on land long inhabited by Indigenous Peoples, most recently the Massachusett Tribe, and on property purchased with wealth from goods produced by enslaved persons.

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We are committed to the Olmstedian principle that everyone is entitled to open space, so our gates are open to everyone, every day, free of charge.

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The Arnold Arboretum has been funded by the generosity of the supporting public since our founding in 1872. Give today and continue that legacy.

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