Polish Oak Quercus robur
Other Common Name(s):
Previously known as:
- Quercus pedunculata
- Phonetic Spelling
- KWER-kus ROH-bur
- This plant has low severity poison characteristics.
- See below
- Description
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English Oak is a large, broadleaf deciduous tree that is a member of the white oak group. This tree has a broad-spreading, rounded crown, and grows 40 to 70 feet tall and equally as wide. The trunk of the tree is short, rounded, and sturdy, and the bark is grayish-brown to black and deeply fissured. The flowers are separate male and female catkins that emerge in the spring as the leaves appear. The leaves are alternate, dark green, small, and measure only 3 to 5 inches long. They have 3 to 7 pairs of deeply rounded lobes. The distinguishing feature of the leaf is the small auricular or "ear-like lobes" at the leaf base. The fruits are oval, 1-inch-long acorns that appear on a long stalk. The cup or cap covers about 1/4 to 1/3 of the acorn.
The English Oak is native to woodland areas from the British Isles to the Caucasus. It was brought to North America in the 1600s from Europe and has been an important lumber tree for furniture and shipbuilding. It is now found in the eastern and northwestern United States and southeastern and southwestern Canada. It is thought to be potentially invasive in some natural areas of the United State, but reportedly actual naturalization is rare. It may be found along roadsides, pastures, edges of forests, and woodlands.
The genus name, Quercus, is the Latin name for oak trees. The specific epithet, robur, is Latin and means "robust' and references the strength and hardwood of this tree.
This tree prefers moist, well-drained, loam soils, and full sun. It will adapt to a wide range of soil types and conditions. This tree is susceptible to powdery mildew in humid climates.
The leaves of the English Oak closely resemble the White Oak. The English Oak has shorter petioles and small auricular lobes at the base of the leaf. The stalks on the acorns are thin and longer than the White Oak. It may take 20 to 30 years for the English Oak tree to bear its first acorns.
It is a host plant for the larvae of the Imperial moth (Eacles imperialis), as well as numerous butterflies, including Banded hairstreak (Satyrium calanus), Edward's hairstreak (Satyrium edwardsii), Gray hairstreak (Strymon melinus), White-m hairstreak (Parrhasius malbum), Horace's duskywing (Erynnis horatius), and Juvenalis duskywing (Erynnis juvenalis).
English oak is considered to be a low-maintenance tree with few problems. It's an excellent specimen or shade tree for large lawns, parks, and public areas. The cultivar, 'Fastigiata,' or Upright English Oak is commonly used in the landscape because of its columnar habit.
Seasons of Interest:
Bark: Winter Bloom: Spring Foliage: Spring, Summer, and Fall Fruits: Fall, after tree age is 25 to 30 years old
Quick ID Hints:
- large deciduous tree, 40 to 70 feet tall and equally as wide
- grayish-brown to black bark with fissures, furrows, and ridges
- small, dark green leaves with 3 to 7 pairs of deeply rounded lobes and small auriculate lobes at the base of the leaf
- bluish-green on the undersides of the leaf and has a short petiole
- yellowish-green male and female catkins emerge in the spring with the leaves
- oval acorns measuring 1 inch long and appear on 1 to 3-inch long stalks and have a cap that covers 1/4 to 1/3 of the acorn
Insects, Diseases, and Other Plant Problems: The insects that may potentially be found on the English Oak include scales, oak skeletonizers, leaf miners, galls, oak lace bugs, borers, caterpillars, and nut weevils. Oak trees are susceptible to a large number of diseases. Oak wilt, chestnut blight, shoestring root rot, anthracnose, oak leaf blister, cankers, leaf spots, and powdery mildew may occur.
The English Oak is known to have escaped and seeded in the landscape in British Columbia. Ontario, Nova Scotia, Maine, New Hampshire, Massachusetts, New York, Pennsylvania, and Ohio.
- See this plant in the following landscape:
- Cultivars / Varieties:
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- 'Attention'
Columnar tree with better mildew resistance
'Fastigiata'
- 'Variegata'
Variegated leaves
Upright, columnar deciduous tree that makes a striking landscape specimen - 'Attention'
- 'Attention', 'Fastigiata', 'Variegata'
- Tags:
- Cultivars / Varieties:
-
- 'Attention'
Columnar tree with better mildew resistance
'Fastigiata'
- 'Variegata'
Variegated leaves
Upright, columnar deciduous tree that makes a striking landscape specimen - 'Attention'
- 'Attention', 'Fastigiata', 'Variegata'
- Tags:
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Attributes:
- Genus:
- Quercus
- Species:
- robur
- Family:
- Fagaceae
- Uses (Ethnobotany):
- High-quality wood for furniture, tool making and shipbuilding. Acorns were roasted to make an inferior coffee substitute. Used in the leather tanning process.
- Life Cycle:
- Perennial
- Woody
- Recommended Propagation Strategy:
- Seed
- Country Or Region Of Origin:
- Europe, Northern Africa, and Western Asia
- Distribution:
- Native: Albania, Austria, Baltic States, Belarus, Belgium, Bulgaria, Central European Russia, Czechoslovakia, Denmark, East European Russia, Finland, France, Germany, Great Britain, Hungary, Ireland, Italy, Netherlands, North Caucasus, North European Russia, Northwest European Russia, Norway, Poland, Portugal, Romania, South European Russia, Spain, Sweden, Switzerland, Transcaucasus, Turkey, Ukraine, and Yugoslavia. Introduced: Canada--British Columbia, New Brunswick, Nova Scotia, Prince Edward Island; Canary Islands, Madeira, New Zealand, and the United States.
- Wildlife Value:
- 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. Green oak moth ( Tortrix viridana ) feeds on oak leaves in its caterpillar form and then rolls itself up in a leaf to pupate. The caterpillar is prey to four speices of ichneumon wasps. Gall wasps also lay their young inside leaves causing the plant to create oak apples or galls. Acorns are eaten by many birds and mammals which in turn attract birds of prey like owls and hawks. Woodpeckers feed on insects in the bark.
- Play Value:
- Shade
- Wildlife Food Source
- Dimensions:
- Height: 40 ft. 0 in. - 70 ft. 0 in.
- Width: 40 ft. 0 in. - 70 ft. 0 in.
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Whole Plant Traits:
- Plant Type:
- Poisonous
- Tree
- Woody Plant Leaf Characteristics:
- Deciduous
- Habit/Form:
- Oval
- Rounded
- Spreading
- Growth Rate:
- Medium
- Maintenance:
- Low
- Texture:
- Medium
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Cultural Conditions:
- Light:
- Full sun (6 or more hours of direct sunlight a day)
- Soil Texture:
- Clay
- High Organic Matter
- Loam (Silt)
- Sand
- Soil pH:
- Acid (<6.0)
- Alkaline (>8.0)
- Neutral (6.0-8.0)
- Soil Drainage:
- Good Drainage
- Moist
- Available Space To Plant:
- more than 60 feet
- NC Region:
- Coastal
- Mountains
- Piedmont
- USDA Plant Hardiness Zone:
- 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b
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Fruit:
- Fruit Color:
- Brown/Copper
- Gold/Yellow
- Green
- Fruit Value To Gardener:
- Showy
- Display/Harvest Time:
- Fall
- Fruit Type:
- Nut
- Fruit Length:
- 1-3 inches
- Fruit Width:
- < 1 inch
- Fruit Description:
- The fruits are acorns that measure 0.8 to 1.2 inches long and appear yellowish-green to brown. The acorns are elongated and egg-shaped. They appear on a stalk that measures 1 to 4 inches long. The cup covers about 1/4 to 1/3 of the nut. The acorns appear singularly or in clusters of 2 to 5. The acorns mature in one season, but the tree is usually about 25 to 30 years old before the acorns appear.
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Flowers:
- Flower Color:
- Gold/Yellow
- Green
- Flower Inflorescence:
- Catkin
- Insignificant
- Flower Bloom Time:
- Spring
- Flower Size:
- 1-3 inches
- Flower Description:
- The flowers are male and female catkins that emerge with leaves in the spring. The male flowers are slender, yellowish-green, 2 to 3 inches long, drooping, and appear in elongated clusters. The female flowers are very small and appear on short spikes in clusters of 3 to 4 at the leaf axils.
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Leaves:
- Woody Plant Leaf Characteristics:
- Deciduous
- Leaf Color:
- Blue
- Green
- Leaf Feel:
- Glossy
- Smooth
- Leaf Value To Gardener:
- Showy
- Deciduous Leaf Fall Color:
- Brown/Copper
- Gold/Yellow
- Leaf Type:
- Simple
- Leaf Arrangement:
- Alternate
- Leaf Shape:
- Oblong
- Obovate
- Leaf Margin:
- Entire
- Lobed
- Hairs Present:
- Yes
- Leaf Length:
- 3-6 inches
- Leaf Width:
- 1-3 inches
- Leaf Description:
- The leaves are small and measure 3 to 5 inches long. They are alternate, simple, and have 3 to 7 pairs of deep-rounded lobes with very short petioles. The distinguishing feature is the "ear lobes" that appear at the base of the leaf. Leaves are dark green on the upper surface and bluish-green underneath. The leaves may appear glossy or dull, smooth, and sparsely pubescent. The leaf color will remain green into the fall, then turn yellow and brown, and will persist through the winter months.
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Bark:
- Bark Color:
- Black
- Dark Brown
- Dark Gray
- Surface/Attachment:
- Fissured
- Furrowed
- Ridges
- Bark Description:
- The trunk of the tree is short, and the bark is grayish-brown to black and deeply fissured with age.
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Stem:
- Stem Color:
- Brown/Copper
- Stem Is Aromatic:
- No
- Stem Buds:
- Smooth/Hairless
- Stem Bud Terminal:
- Cluster of terminal buds
- Stem Surface:
- Smooth (glabrous)
- Stem Description:
- Twigs are yellow-brown and glabrous. The brown buds are angled, short, oval, and smooth, with each scale margin being light brown.
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Landscape:
- Landscape Location:
- Lawn
- Meadow
- Woodland
- Landscape Theme:
- Butterfly Garden
- Nighttime Garden
- Pollinator Garden
- Design Feature:
- Shade Tree
- Specimen
- Street Tree
- Attracts:
- Butterflies
- Moths
- Pollinators
- Predatory Insects
- Small Mammals
- Songbirds
- Resistance To Challenges:
- Deer
- Drought
- Problems:
- Problem for Horses
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Poisonous to Humans:
- Poison Severity:
- Low
- Poison Symptoms:
- Stomach pain, constipation and later bloody diarrhea, excessive thirst and urination if young leaves or raw acorns eaten.
- Poison Toxic Principle:
- Gallotannins, quercitrin, and quercitin.
- Causes Contact Dermatitis:
- No
- Poison Part:
- Fruits
- Leaves