October 1, 2019
As curator, I often find myself drawn not necessarily to the largest, most prominent, or most ornamental specimens in the living collections, but to the rare or unusual: those botanical oddities that an informed tree enthusiast will also find similarly remarkable when exploring the Arboretum.
Such is the case with a large willow oak (Quercus phellos) growing on the outskirts of the oak collection. With a native range extending through much of the southeastern United States, the willow oak is a common sight to many Americans. In some areas it is common enough to illicit derision and status as a “weed tree.” In Northern Illinois, however, it is a rare sight. Many of the southeastern oak species struggle to tolerate the region’s bitter cold winters and perpetually wet springs, suffering from frost cracks or root system failure after a particularly challenging year. Still, this tree persists, having survived in its current location for over 40 years.
When I observe this tree, I find myself wondering why is it able to thrive here? Does its position along the woodland edge provide ample protection from the elements? The Arboretum received this plant from Princeton Nurseries in 1974, and though its exact provenance is unknown to us, it may very well have begun life as a seed from one of the northernmost occurrences of the species in New Jersey, potentially with some genetics providing additional cold tolerance. Both site selection and provenance selection are important for the survival of a tree.
This tree is one of my favorite to showcase on tours of the oak collection. Despite its relative commonality, novices are surprised to learn that this tree, with its short, thin unlobed leaves, is truly a species of oak tree, whereas experts are surprised to find the tree growing in the Arboretum’s collections at all. Perhaps most of all, I like this tree for what it represents: the importance of testing new species and a willingness to accept failure so long as it leads to more informed future decision making. Such experimentation is critical to the Arboretum’s mission to collect and study trees and inspire future tree champions.
Matt Lobdell is the curator of living collections at The Morton Arboretum.