Quercus suber
Common Name: cork oak 
Type: Tree
Family: Fagaceae
Native Range: Northern Africa, southern Europe
Zone: 8 to 10
Height: 40.00 to 70.00 feet
Spread: 40.00 to 70.00 feet
Bloom Time: April
Bloom Description: Yellow-green
Sun: Full sun
Water: Dry to medium
Maintenance: Low
Suggested Use: Shade Tree, Street Tree
Flower: Insignificant
Fruit: Showy
Tolerate: Drought

Culture

Winter hardy to USDA Zones 8-10 where it is best grown in acidic, dry to medium, well-drained loams in full sun. Tolerates some part shade. Tolerates drought. Avoid wet, poorly-drained soils. This tree is not winter hardy to the St. Louis area.

Noteworthy Characteristics

Quercus suber, commonly called cork oak, is a medium sized evergreen oak that is native to the central and western Mediterranean region. Bark from this oak is commercially harvested and processed to produce a variety of products including wine bottle corks. Trees are commercially grown in plantations in several European and African countries, most notably in Portugal and Spain. Cork is usually not harvested until a tree reaches the age of at least 30-40 years. Thereafter, bark is stripped from a tree once every 9-11 years. Cork oak was introduced into the U. S. in the 1600s where it has over time been planted in warm winter locations, often in somewhat dry conditions, from Maryland to California. Trees typically mature to 40-70’ tall. Regardless of commercial value, this is an ornamentally attractive oak. Leathery, wavy-toothed, ovate, shiny dark green leaves (to 2-4” long) are gray-tomentose below. Thick, rough, deeply fissured, corky bark with reddish-brown furrows has a unique beauty, particularly on older trees. Over time, bark will grow to as much as 12” thick. Insignificant monoecious flowers appear in spring in male catkins (2-3” long) and in short-stalked female clusters. Fruits are narrow oval-oblong acorns (to 1.25” long).

Genus name comes from the classical Latin name for oak trees.

Problems

Oaks in general 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.

Garden Uses

Large oak for streets, residential areas and parks.