May 2025: Willow Oak

By Greg Doyle, Andy Mead, and Tyson Gregory

Willow Oaks flanking sidewalks at the University of Kentucky at the intersection of Woodland Avenue and Hilltop Avenue. By Greg Doyle.

These rows of Willow Oaks (Quercus phellos) were planted in the late 1960's as a landscaped shaded walkway to the former Kirwan Blanding dormitories on the University of Kentucky campus. One row leads from the intersection of Woodland Avenue and Hilltop Avenue, while a longer row runs from the intersection of Huguelet Drive and University Drive. 

The Willow Oak is a medium to large tree in the red oak family native to south-central and eastern United States. The University of Kentucky Cooperative Extension characterizes it as an excellent shade tree. It often is found in alluvial areas and swamps, and does best in acidic soils. With our alkaline soils, you

Willow Oaks also line sidewalks on UK's campus at the intersection of Huguelet Drive and University Drive. By Greg Doyle.

should have a soil test before planting one. Many willow oaks in Lexington have died due to improper site conditions. It is a fast-growing tree that is relatively easy to transplant. It can grow in floodplains but tolerates drought. It has no serious insect or pest problems on a good spot, but it gets oak lecanium scale when stressed, which hastens its decline.

Generally, the willow oak is considered an inappropriate species for planting in the Bluegrass Region due to our limestone bedrock which naturally makes our soils more alkaline. This natural phenomenon is compounded further in urban areas by the presence of lime in construction materials like concrete, gravel, and mortar, which leaches out and further increases the soil pH. 

Most trees in the red oak family have

Willow oak leaves. By Greg Doyle.

lobed leaves. The Willow Oak gets its common name from the shape of its leaves that somewhat resemble those of a willow tree; they are narrow and two to four inches long with a bristle-like hair at the end. The leaves turn a golden yellow to reddish for a nice display in the fall.

The tree produces small acorns averaging half an inch in length that are a food source of many ground foragers including chipmunks and squirrels. In heavy mast years, the acorns can cover sidewalks and yards, and may be considered problematic.

Willow Oak Acorns "Bruce K. Kirchoff http://www.uncg.edu/~kirchoff"

Willow Oaks can grow to be 120 feet tall but are more commonly found at 60 to 70 feet tall. The Kentucky champion Willow Oak is in Knox County. It has a crown spread of 106 feet and is 114 feet tall. 

Acorn caps of a Willow Oak. By Greg Doyle.