Common Name: willow oak
Native Range: Southeastern United States
Zone: 5 to 9
Height: 40.00 to 75.00 feet
Spread: 25.00 to 50.00 feet
Bloom Time: April
Bloom Description: Yellow-green
Sun: Full sun
Water: Medium to wet
Suggested Use: Shade Tree, Street Tree, Rain Garden
Tolerate: Clay Soil, Wet Soil, Air Pollution
Easily grown in average, medium to wet, well-drained soils in full sun. Tolerates light shade. Prefers moist well-drained loams, but adapts to a wide range of soil conditions including clays with somewhat poor drainage. Generally tolerant of urban pollution. Trees or seeds for the St. Louis area should come from northern sources because there is some question as to the winter hardiness of this tree throughout USDA Zone 5.
Willow oak is a medium to large, deciduous oak tree of the red oak group that is noted for its oak shape, willow-like leaves and relatively fast growth rate. It is native to the Southeastern United States, typically being found in moist bottomland soils. In Missouri, it is usually found in wet or low woods bordering swamps, streams and canals in a few counties in the far southeastern portion of the state (Steyermark). Willow oak typically grows 40-75’ tall with an oval to rounded crown, but may reach 100’ in ideal conditions. Smooth-edged, bristle-tipped, narrow, green leaves (to 5” long and 1” wide) are willow-like. Leaves turn an undistinguished yellow-brown or dull gold in fall. Fruits are rounded acorn cups (to 1/2” long). Acorns can be an important source of food for wildlife. Insignificant monoecious yellowish-green flowers in separate male and female catkins appear in spring (April) as the leaves emerge. Dark, irregularly-furrowed trunks (gray to dark gray-brown) develop on mature trees.
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, willow oak is generally considered to have good resistance to pests and to be a low-maintenance, long-lived tree.
A medium to large shade tree for large lawns, along streets or in parks. Also effective along ponds or water gardens.