Quercus macrocarpa – Bur Oak

Botanical Name: Quercus macrocarpa

Alternate Name: Burr Oak, Mossycup Oak

The Bur Oak (Quercus macrocarpa) is a hardy, stately, medium to large sized deciduous tree. It gets its name from the fringed cups that hold the acorns that are covered in burs. Another common name is the Mossycup Oak. This tree can grow in a pyramidal shape as a juvenile but becomes more rounded with a wide, spreading crown as it matures. It grows to a height of 60-80 feet tall with a spread of 60-80 feet.

The Bur Oak is native to the central United States as well as and eastern Canada. It is known as a ‘praire species,’ as it is found growing on the edge of prairies where the thick, corky bark will protect it from harsh weather conditions. This oak tree can be found in bottomlands, low woodlands, or stream valleys. It thrives best in the soils found there – usually clay or loam with a high content of organic matter.

The flowers of the Bur Oak are catkins. They are greenish-yellow in color and emerge in the spring as separate male and female flowers, just as the leaves are emerging. The fruits are acorns that grow up to 1 ½  inches in size, and ½ to ¾ of their length is covered by the burred cups. The bark on this tree is brown or gray and is very corky, with deep ridges.

The large leaves are 6-12 inches long and have 5 to 9 irregularly shaped lobes. The fall color is unremarkable and the leaves turn shades of yellow and brown.

The Bur Oak is very adaptable and resistant to very cold temperatures as well as heat and drought.