As the planet warms, how do we decide when a plant is native?

Yale Environment 360: The fate of a tree planted at poet Emily Dickinson's home raises questions about whether gardeners can - or should - play a role in helping plant species migrate in the face of rising temperatures and swiftly changing botanical zones

On rare occasions, the townsfolk of Amherst, Massachusetts, would catch a glimpse of a ghostly figure dressed in white, leaning over to tend her flowers by flickering lantern light. The mysterious recluse, who was better known to neighbors for her exquisite garden than for her lyric poems that revealed a passionate love of nature, differed from fellow 19th-century American writers whose thinking became the bedrock of modern environmentalism. While Thoreau famously declared wild places to be "the preservation of the world," Emily Dickinson was finding nature's truth and power in an ordinary dandelion.

Among the plants that survive on the family property where Dickinson confined herself for much of her adult life are picturesque old trees called umbrella magnolias (Magnolia tripetala) - so named because their leaves, which can reach two feet long, radiate out from the ends of branches like the spokes of an umbrella.