A comprehensive database of Tennessee native plants
Bur Oak, Mossycup Oak
Full sun; medium to dry moisture level; grows in a wide range of soils including medium loam, silt loam, sandy loam, sandy, rocky, and heavy clay; strongly acid to slightly alkaline pH.
70-80 feet height by 70-80 feet spread; blooms in spring with drooping, yellowish-green male catkins, 1-2 inches long, and inconspicuous yellowish-green female spikes; tan-brown acorns, ¾ – 1 ¼ inch long with fringed cup covering ½ or more of the nut, in fall. Acorn matures in a single season.
Growth Rate: Slow; 15-20 feet on average over 20 years.
Maintenance: All oaks are susceptible to a large number of diseases, including oak wilt, oak leaf blister, cankers, leaf spots and powdery mildew. Potential insect pests including scale, oak skeletonizer, leaf miner, oak lace bugs, borers, caterpillars and nut weevils. Notwithstanding these problems, oaks are generally considered to be low maintenance trees.
Propagation: Seed germination code A. Also C(30-60) at 41 degrees F. may be beneficial. Due to a deep taproot, best to simply plant an acorn directly in ground or do container-grown seedlings in deep containers for no more than 1-2 years.
Native Region: Limited areas of Coastal Plain and Interior Low Plateau provinces
Large canopy tree that is one of the most majestic of the native North American oaks with a very wide, open crown. Excellent landscape specimen that is easy to grow. This is a large shade tree for very large lawns or parks. Fall color is an undistinguished yellow-brown. Grows naturally on sandy plains to moist alluvial bottoms and on uplands where it favors limestone soil. Succeeds well even in dry, clay soils and is more tolerant of city conditions than most oaks. Drought tolerant and intolerant of flooding. Macrocarpa comes from Greek words meaning large fruit and reflects fact that acorns of this species are the largest of all native oaks. Average minimum acorn-bearing age is 35 years. Good crops occur every 2-3 years. Common name describes the cup of the acorn which slightly resembles bur of a chestnut. Cultivars available.
Very high wildlife value. Provides food for a wide variety of songbirds, ground birds, waterbirds, and small mammals. As it reaches maturity, provides roosting, loafing and nesting for numerous species of birds. Attracts butterflies.