Underutilized Trees for Urban Use: Quercus michauxii

Council Board Member and Commercial & Consulting Arborist for SavATree Jean Zimmerman provided this superb story and photos. Jean is also an extensively published author (jeanzimmerman.com), centering much of her fiction and nonfiction around the history of Manhattan.

When saplings of swamp chestnut oak (Quercus michauxii) showed up on the streets of Ithaca, New York in 2007, even some knowledgeable arborists might have been surprised. Rarely seen in the colder northern precincts of Zone 5 central New York, Quercus michauxii hails from the Southern United States, where it keeps its feet wet in swamps and mixed hardwood forests. When I encountered striking specimens in the college town recently, I wondered how michauxii had wound up on the streets of “Mythaca.”

“We were adding more oaks to the tree inventory as we strived for greater diversity,” says Council stalwart and former Ithaca City Forester Andy Hillman. “This led us to the chestnut oaks—Quercus montana (chestnut oak), Quercus muehlenbergii (yellow chestnut oak), and Quercus michauxii. It was an experiment that paid off.” Hillman installed four michauxii, planted from #3 pots that cost $15 each, throughout the streets of the municipality.

Thirteen years after planting, the swamp chestnut oaks flourish in Ithaca. Light gray and scaly, the distinctive bark resembles that of its cousin, the white oak. Strips of the bark have traditionally been used for basket weaving, lending the tree one of its common names, “basket oak.” The leaves resemble those of the chestnut oak, leathery to the touch, but have dense, evenly distributed hairs underneath, and vary in length from 3 to 11 inches, with around a dozen pairs of large rounded teeth. The nut, ovoid to oblong and light brown, is half encased in a deep, warty, hairy, scaly cup that is about an inch wide. One to three acorns grow on a short stalk.

Bovines must not disdain warts, hairs, or scales, since cows munch contendedly on the acorns, giving michauxii another nickname: cow oak. So sweet is their taste, supposedly there is no need to boil the acorns first before grinding them for flour.

While Ithaca’s swamp chestnut oaks now stand at a respectable 20 feet tall, they can grow quite large. The most celebrated is a 140 by 115 foot national champion in Big Oak State Park in Missouri.

Professor Nina Bassuk, program leader of the Urban Horticulture Institute at Cornell University, has monitored these michauxii since they were planted, and is a fan. “Because it is in the white oak family, it’s not as susceptible to oak wilt.” She adds, “The form is great. It grows pretty well—it’s a big tree. It tolerates wet times and dry times, is often drought tolerant, though you have to plant it in soil that’s not overly alkaline.”

Despite its Southern U.S. origins, climate change has allowed the swamp chestnut oak a toehold in the microclimates of northern cities. The tree does need care. “With hindsight,” says Hillman, “I would have looked for sites with more moisture and lower pH. I think that would have alleviated the chlorosis we sometimes see now.” He would recommend Q. michauxii for moister sites with more soil, rather than relatively narrow tree lawns.

“This is a stately tree deserving of greater consideration in contemporary landscapes,” states Michael Dirr in his Manual of Woody Plants. “Why is this tree not more common in gardens?”

Professor Bassuk concurs: “It should be planted more,” she says. ?