Willow Oak


Immature acorns

Introduction

The willow oak can turn out to be a towering tree that dwarfs anything beside it, and in this form it is a centerpiece of any forest, grove or yard as it gives plenty of food for wildlife and copious amounts of shade.

More detail: Willow oaks’s Tree of the Month.

Common Name

Willow oak

Latin Name

Quercus phellos

Leaf

Alternate, simple, 2 to 5 inches long, willow-like in shape with a bristle tip

Flower

Male flowers are borne on slender yellow-green catkins*; female flowers are borne on very short auxiliary spikes

Fruit/nut

Acorns are very small, 1/4 to 1/2 inch across, nearly round and yellow-green, turning tan when older. The caps are thin, saucer-like and cover only a quarter of the acorn

Twig/branches

Slender, hairless, olive-brown in color when young. The multiple terminal buds are very small, reddish brown and sharp-pointed

Bark

On young stems, smooth, gray and tight; later becoming darker and forming irregular rough ridges and furrows

Form

Dense oblong crown when grown out in the open. Normally has a pyramidal, rounded shape

Size

Typically matures at 40 to 60 feet tall and 35 feet across, but it can grow up to 120 feet tall

Native Range

Ranges along the Coastal Plain from New Jersey south to Georgia and northern Florida, west to eastern Texas, and north to southeastern Oklahoma and western Tennessee

Type

Medium-large deciduous

Seasonal Colors

Leaves turn yellow-brown in fall

Soil

Prefers acidic, moist, sandy, well-drained, wet, clay soils

Light

Grows best in full sun

Similar Species

Water oak, laurel oak, shingle oak, Darlington oak

Pests and Diseases

Perhaps the most serious insect pests are trunk borers such as the red oak borer, carpenterworm and the living-beech borer. Common cankers attack willow oaks and are caused by the fungus Polyporus hispidus.

Rebate Eligibility

$100

Of Note

Willow oak is a major supplier of food for game animals such as ducks, squirrels, deer and turkey.

The tree is planted widely around the D.C. area as street trees along roads and parks.

Photo Credits

Jim Conrad
US Government
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