The Bur Oak is a massive, majestic species, usually wider than it is tall, and prized as a dependable shade tree. Otherwise dark green, the Bur Oak’s foliage transforms to fierce shades of golden-brown in the autumn. This pioneering tree is as resilient as it is gigantic, found farther north than any other oak species in the New World. Imposing and very durable, the Bur Oak is a surefire long-term investment that, once planted, sticks around for centuries.
The Bur Oak (sometimes spelled “Burr Oak” and alternatively known as “Mossycup Oak”) is widespread throughout North American’s Atlantic coastal plains, with the vast majority of this species found around the eastern Great Plains, near the Great Lakes, and along the Mississippi/Missouri/Ohio valley. The tree has a 3-8 hardiness zone rating and thrives given full sun and medium to dry, well-drained soils. Usually planted upland, the Bur Oak needs its space; it typically grows in open uplands or in forests where there is a break in the canopy. It is among the most fire-tolerant of trees, making it an invaluable survivor in the Midwest where early spring and late autumn fires often occur.
Scientifically classified as Quercus Macrocarpa and ranked in the Fagaceae family, this specimen is characterized by its broad crown (alternatively irregular or rounded) which typically rears up to 60-80 ft. (though some specimens have been known to tower over 100 ft.). Its trunk is enormous, layered with a furrowed gray bark and interspersed with heavy, widespread horizontal branches. The leaves are long and veined, their lobes separated by deep sinuses. Like the majority of the oak variations, the Bur Oak produces yellow-green catkins from April to May which quickly fade to reveal the tree’s wild and wooly fruit. The Bur Oak’s acorns are the largest of all native oaks, with very deeply fringed cups, and from which this tree has derived its name (the acorn cups resemble the spiny burs of chestnuts). These seeds are a beloved food source for a variety of wildlife, including cattle, porcupines, and black bears; bears sometimes will literally tear off entire branches to get to the acorns. The Bur Oak produces only these seeds in heavy amounts every few years, an interesting evolutionary strategy meant to counter the habitual attempts of seed predators, and thereby ensuring the tree’s propagation.
Photos Paul Wray, Iowa State University, Bugwood.org
Photos Copyright © Horticopia, Inc. 2017
This Tree's Zone: 3 to 8
Your Growing Zone:
|Bloom Time||April to May|
|Shape||Irregular to round|
|Size||60 to 80 feet|
|Spread||60 to 80 feet|