Willow Oak

Quercus phellos L.



All photographs are copyrighted and are the property of E. Brunner.

Family:  Fagaceae

Native or Introduced to Illinois:  native 

Natural Habit in Illinois:  along streams; around lakes and ponds

Leaf:  The leaves are simple, alternate, deciduous, elongated and slender, with smooth edges; they are light green and shiny above, dull and paler below with distinct venation. 

Flower:  Brown, faded flower color.

Fruit:  The small, round, brown acorns are usually produced singly or in pairs with a shallow, saucer-shaped cap.  The overlapping scales that make up the cap are thin, hairy, and dark red.  There are about 462 acorns per pound.

Bark/Twig:  It has thick, smooth, light-reddish bark when young; which becomes roughened and divided into narrow ridges on older trees. 

Size/Form/Shape:  Willow oak is a medium to large-sized tree that grows up to over 100 feet tall, with a trunk 3 to 6 feet in diameter.

County Distribution Map for Illinois:  


Sources for the Sullivan Middle School Tree Identification Guide were obtained though the use of the following sites:

The information below is from the National Arbor Day Foundation.  This information can be viewed in the original (source) form by visiting The National Arbor Day Foundation at http://www.arborday.org.

Sun Exposure:  This oak does well in Full sun.
Soil Type:  The Willow Oak grows in acidic, loamy, moist, clay, sandy, wet, well-drained soils. This tree is drought tolerant.
Moisture:  Normal moisture requirement, but with some drought tolerance.
Growth Rate:  This tree grows at a medium growth rate.

Hardiness Zones: 5 - 9
This oak can be expected to grow in the zones shown in color in the arborday.org zone map.

The Black Walnut can be expected to grow in the temperature extremes of Hardiness Zones 4 - 9