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Native alternative(s) for Quercus suber:
Quercus virginiana Form of mature tree (Seminole County, GA)-Late Spring
Plants that fill a similar niche:
Quercus falcata Tree form (Greensboro, NC)-Mid Fall
Quercus hemisphaerica Form (Moore County, NC)-Early Fall
Quercus alba Full Form

Quercus suber

Common Name(s):

Previously known as:

  • Quercus corticosa
  • Quercus suberosa
Phonetic Spelling
KWER-kus SOO-ber
Description

Cork Oak is a medium to large size attractive broadleaf evergreen shade tree that grows 70 to 100 feet tall and equally as wide. It has a short trunk, thick branches, and a rounded crown. Corky bark covers the trunk and major limbs of the tree. The spongy bark of mature trees is used to make wine bottle corks, cork flooring, and other items. The cork is harvested when the tree reaches 30 to 40 years of age and then every 9-11 years for up to 12 times within its lifetime. 

It is native to western Africa and southwestern Europe and is found in forests and open woodlands. The Cork Oak is the National Tree of Portugal where half of the world's commercial cork is produced. There are plantations in some European and African countries especially Portugal and Spain that commercially grow the cork oak tree.

The genus name, Quercus, is the Latin name for oak trees. The epithet name, suber, is Latin and is similar to the Greek word syphar which means "a piece of old skin" or "a piece of wrinkled skin."

The cork oak is best grown in acidic, well-drained, moist to dry soils in full sun to partial shade. It is low maintenance, deer resistant, and drought tolerant.  Because of the high levels of tannins in the leaves, bark, and acorns, oaks are toxic to horses.

The cork oak bark is light gray and thick, with reddish-brown furrows. The leaves of this tree are elliptic to ovate with wavy margins, leathery, sparsely toothed, and shiny dark green on the upper surface. The undersides are white with grayish hairs. Appearing in the spring, the male flowers are inconspicuous yellow-greenish catkins, and the female flowers are short clusters. The female flowers produced long, narrow acorns with a shaggy cap that are harvested in the fall.

The world's largest Cork Oak tree is in a small village in Portugal and was planted in 1783. The tree is known as Sobreiro Monumental or Whistler's Tree and is over 230 years old. The tree is 53 feet tall and 14 feet in diameter. Its cork has been collected over 20 times. In 1991, the tree produced 2646 pounds of raw cork which is enough cork to stopper 100,000 wine bottles.

In the United States, it can be grown in warmer winter areas and makes an attractive shade tree.

Seasons of Interest:

Bark:  Winter     Foliage:  Spring, Summer, Fall, and Winter     Fruits:  Fall

Quick ID Hints: 

  • light gray bark with reddish-brown furrows, thick layers of cork
  • light gray-brown stems, gray fuzz, reddish-brown buds, triangular and pointed
  •  alternate, simple, leathery, ovate to elliptical dark green leaves, undersides are whitish and fuzzy, margins are sparsely toothed and wavy
  • yellow-greenish, 2-to-3-inch chainlike, male catkin flowers and small clusters of female flowers
  • fruit is a 1 to 1.5-inch long, narrow acorn with a scaly cap

Insects, Diseases, and Other Plant Problems: Insects that may potentially be troublesome include scales, oak skeletonizer, leaf miner, galls, oak lace bugs borers, caterpillars, and nut weevils.  Oaks are susceptible to many diseases including oak wilt, chestnut blight, shoestring root rot, anthracnose, oak leaf blister, cankers, leaf spots, and powdery mildew. 

VIDEO created by Ryan Contreras for “Landscape Plant Materials I:  Deciduous Hardwoods and Conifers or Landscape Plant Materials II:  Spring Flowering Trees and Shrubs” a plant identification course offered by the Department of Horticulture at Oregon State University

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Cultivars / Varieties:
Tags:
#evergreen#shade tree#drought tolerant#interesting bark#wildlife plant#moths#spring flowers#winter interest#nighttime garden#fruits fall#pollinator plant#leathery leaves#larval host plant#evergreen tree#butterfly friendly#moth larvae#problem for horses#banded hairstreak butterfly#gray hairstreak butterfly#imperial moth#juvenal’s duskywing butterfly#edward’s hairstreak butterfly#white-m hairstreak butterfly#horace’s duskywing butterfly#landscape plant sleuths course
 
Cultivars / Varieties:
Tags:
#evergreen#shade tree#drought tolerant#interesting bark#wildlife plant#moths#spring flowers#winter interest#nighttime garden#fruits fall#pollinator plant#leathery leaves#larval host plant#evergreen tree#butterfly friendly#moth larvae#problem for horses#banded hairstreak butterfly#gray hairstreak butterfly#imperial moth#juvenal’s duskywing butterfly#edward’s hairstreak butterfly#white-m hairstreak butterfly#horace’s duskywing butterfly#landscape plant sleuths course
  • Attributes:
    Genus:
    Quercus
    Species:
    suber
    Family:
    Fagaceae
    Uses (Ethnobotany):
    Bark is used to make corks and is harvested from at least 30 year old trees every 9-11 years.
    Life Cycle:
    Woody
    Recommended Propagation Strategy:
    Seed
    Stem Cutting
    Country Or Region Of Origin:
    Western and Central Mediterranean
    Distribution:
    Native: Algeria, Corse, France, Italy, Morocco, Portugal, Sardegna, Sicilia, Spain, and Tunisia. Introduced: Baleares and Canary Islands.
    Wildlife Value:
    In its native habitat, the cork oak supports a wide range of wildlife including many endangered species of birds and felines and the acorns are a high-value food source for mammals. Oak trees support a wide variety of Lepidopteran. You may see Imperial Moth (Eacles imperialis) larvae which have one brood per season and appear from April-October in the south. Adult Imperial Moths do not feed. Banded Hairstreak (Satyrium calanus), which have one flight from June-August everywhere but Florida where they emerge April-May. Edward's Hairstreak (Satyrium edwardsii), has one flight from May-July in the south and June-July in the north. Gray Hairstreak (Strymon melinus), has three to four flights in the south from February-November and two flights in the north from May-September. White-M Hairstreak (Parrhasius m-album) has three broods in the north from February-October. Horace’s Duskywing (Erynnis horatius) has three broods in Texas and the deep south from January-November, and two broods in the north from April-September. Juvenal’s Duskywing (Erynnis juvenalis) has one brood from April-June, appearing as early as January in Florida.
    Play Value:
    Wildlife Cover/Habitat
    Wildlife Food Source
    Wildlife Larval Host
    Wildlife Nesting
    Edibility:
    Acorns are edible once the tannins have been boiled or leached out.
    Dimensions:
    Height: 70 ft. 0 in. - 100 ft. 0 in.
    Width: 70 ft. 0 in. - 100 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Tree
    Woody Plant Leaf Characteristics:
    Broadleaf Evergreen
    Habit/Form:
    Erect
    Multi-stemmed
    Rounded
    Spreading
    Growth Rate:
    Slow
    Maintenance:
    Low
    Texture:
    Medium
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Soil Texture:
    Clay
    Loam (Silt)
    Sand
    Soil pH:
    Acid (<6.0)
    Neutral (6.0-8.0)
    Soil Drainage:
    Good Drainage
    Moist
    Occasionally Dry
    Available Space To Plant:
    more than 60 feet
    NC Region:
    Coastal
    USDA Plant Hardiness Zone:
    8b, 8a, 9b, 9a, 10b, 10a
  • Fruit:
    Fruit Color:
    Brown/Copper
    Fruit Value To Gardener:
    Edible
    Showy
    Display/Harvest Time:
    Fall
    Fruit Type:
    Nut
    Fruit Length:
    1-3 inches
    Fruit Width:
    < 1 inch
    Fruit Description:
    The fruit is an oval to oblong, narrow, acorn with a shaggy cup-shaped cap that measures up to 1 to 1.5-inches-long. The cup covers half of the nut. The fruits mature in one season.
  • Flowers:
    Flower Color:
    Gold/Yellow
    Green
    Flower Inflorescence:
    Catkin
    Insignificant
    Flower Bloom Time:
    Spring
    Flower Size:
    1-3 inches
    Flower Description:
    There are male and female flowers. The male is 2- to 3-inch-long catkins. The female flowers are small, short, clusters of 2 to 4 in the leaf axils.
  • Leaves:
    Woody Plant Leaf Characteristics:
    Broadleaf Evergreen
    Leaf Color:
    Gray/Silver
    Green
    Leaf Feel:
    Leathery
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Leaf Shape:
    Elliptical
    Oblong
    Ovate
    Leaf Margin:
    Dentate
    Undulate
    Hairs Present:
    Yes
    Leaf Length:
    3-6 inches
    Leaf Width:
    1-3 inches
    Leaf Description:
    The leaves are evergreen, leathery, wavy, sparsely toothed, simple, oval to elliptic, and dark green above. The undersides are gray and hairy. Leaf margins may have no teeth to sparse teeth, wavy, and downcurved. The leaves measure 2 to 4 inches long.
  • Bark:
    Bark Color:
    Light Brown
    Light Gray
    Red/Burgundy
    Surface/Attachment:
    Fissured
    Furrowed
    Ridges
    Spongy
    Bark Description:
    The bark is light gray with reddish-brown furrowed, ridged, thick, and corky. It develops thick layers of cork up to 12 inches thick. is also rough, deeply fissured, and grows up to 12 inches thick.
  • Stem:
    Stem Color:
    Gray/Silver
    Stem Is Aromatic:
    No
    Stem Surface:
    Hairy (pubescent)
    Stem Description:
    The stems are light gray and have gray fuzzy hairs. The buds are reddish-brown, triangular, pointed, clustered, and have gray fuzz.
  • Landscape:
    Landscape Location:
    Coastal
    Lawn
    Meadow
    Landscape Theme:
    Butterfly Garden
    Nighttime Garden
    Pollinator Garden
    Winter Garden
    Design Feature:
    Shade Tree
    Street Tree
    Attracts:
    Butterflies
    Moths
    Pollinators
    Small Mammals
    Songbirds
    Resistance To Challenges:
    Deer
    Drought
    Dry Soil
    Problems:
    Problem for Horses