Common Name: bur oak
Native Range: Northern and central United States, southeastern Canada
Zone: 3 to 8
Height: 60.00 to 80.00 feet
Spread: 60.00 to 80.00 feet
Bloom Time: April
Bloom Description: Yellowish-green
Sun: Full sun
Water: Dry to medium
Suggested Use: Shade Tree, Rain Garden
Tolerate: Drought, Clay Soil, Dry Soil
Easily grown in average, dry to medium, well-drained soils in full sun. Prefers moist well-drained loams, but adapts to a wide range of soil conditions. Good drought tolerance. May take up to 35 years for this tree to bear a first crop of acorns.
Bur oak or mossycup oak is one of the most majestic of the native North American oaks. It is a medium to large sized deciduous oak of the white oak group that typically grows 60-80’ (less frequently to 150’) tall with a broad-spreading, rounded crown. Acorn cups are covered with a mossy scale or bur near the rim, hence the common names. It is native to a variety of habitats in central and eastern North America. Best growth occurs in bottomland soils, particularly in the Ohio River valley. In Missouri, it typically occurs in low woods and stream valleys in the Ozark region, but on dry upland soils in the unglaciated parts of the state north of the Missouri River (Steyermark). Insignificant monoecious yellowish-green flowers in separate male and female catkins appear in spring as the leaves emerge. Fruits are oval acorns (to 1 1/2” long), with fringed, burry cups that extend to approximately 1/2 to 3/4 the acorn length. Acorns are an important source of food for wildlife. Leathery, dark green leaves (6-12” long) with 5-9 rounded lobes are variable in shape, but usually have a pair of deep central sinuses that extend nearly to the midrib giving the leaf a waisted appearance. Fall color is an undistinguished yellow-brown. Twigs sometimes are ridged with corky wings.
Macrocarpa comes from the Greek words macro meaning large and carpa meaning fruit in reference to the large acorn size.
Oaks are susceptible to a large number of diseases, including oak wilt, chestnut blight, shoestring root rot, anthracnose, oak leaf blister, cankers, leaf spots and powdery mildew. Potential insect pests include scale, oak skeletonizer, leaf miner, galls, oak lace bugs, borers, caterpillars and nut weevils. Notwithstanding the aforementioned, bur oak is generally considered to be a low-maintenance, long-lived tree.
A large shade tree for very large lawns or parks.