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Japanese Blue Oak Lithocarpus glaber

Other Common Name(s):

Phonetic Spelling
KWER-kus GLAW-kuh
This plant has low severity poison characteristics.
See below
Description

Ring Cup Oak is an evergreen oak from Asia. It can grow as a small tree or large shrub. In cultivation, it generally grows 20-30 feet high. The leaves are sensitive to cold damage. This tree tolerates a wide range of soils including wet clay soils and does best in full sun.

The leaves are attractive and acorns are produced in fall which attracts wildlife. Use as a small shade tree, a street tree, or for privacy and screening.

 

See this plant in the following landscape:
Cultivars / Varieties:
Tags:
#evergreen#shade tree#full sun tolerant#deer resistant#acorns#oak#screening#clay soils tolerant#wildlife friendly
 
Cultivars / Varieties:
Tags:
#evergreen#shade tree#full sun tolerant#deer resistant#acorns#oak#screening#clay soils tolerant#wildlife friendly
  • Attributes:
    Genus:
    Lithocarpus
    Species:
    glaber
    Family:
    Fagaceae
    Life Cycle:
    Woody
    Recommended Propagation Strategy:
    Seed
    Country Or Region Of Origin:
    Eastern and southern Asia
    Wildlife Value:
    Mildly resistant to damage by deer. Wildlife eats the acorns.
    Edibility:
    Acorns (nuts) are edible after tannins are leached or boiled out
    Dimensions:
    Height: 20 ft. 0 in. - 30 ft. 0 in.
    Width: 10 ft. 0 in. - 15 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Poisonous
    Tree
    Woody Plant Leaf Characteristics:
    Broadleaf Evergreen
    Habit/Form:
    Erect
    Multi-stemmed
    Oval
    Rounded
    Growth Rate:
    Slow
    Maintenance:
    Medium
    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
    Occasionally Wet
    Available Space To Plant:
    12-24 feet
    NC Region:
    Coastal
    Piedmont
    USDA Plant Hardiness Zone:
    8a, 8b, 9a, 9b
  • Fruit:
    Fruit Color:
    Brown/Copper
    Display/Harvest Time:
    Fall
    Fruit Type:
    Nut
    Fruit Length:
    < 1 inch
    Fruit Width:
    < 1 inch
    Fruit Description:
    Acorns are up to 3/4 inch long. The cup has 5-6 concentric rings and covers approximately 1/3 of the nut. They grow singly or in clusters of 2 or 3.
  • Flowers:
    Flower Color:
    Gold/Yellow
    Flower Inflorescence:
    Catkin
    Insignificant
    Flower Bloom Time:
    Spring
    Flower Description:
    Separate male and female catkins in spring.
  • Leaves:
    Woody Plant Leaf Characteristics:
    Broadleaf Evergreen
    Leaf Color:
    Gray/Silver
    Green
    Purple/Lavender
    Red/Burgundy
    Leaf Feel:
    Glossy
    Leathery
    Leaf Value To Gardener:
    Long-lasting
    Showy
    Deciduous Leaf Fall Color:
    Gold/Yellow
    Leaf Type:
    Simple
    Leaf Arrangement:
    Opposite
    Leaf Shape:
    Elliptical
    Oblong
    Leaf Margin:
    Entire
    Serrate
    Hairs Present:
    Yes
    Leaf Length:
    3-6 inches
    Leaf Width:
    1-3 inches
    Leaf Description:
    4-8 inch long by 2-4 inches wide elliptical to oblong leaves appear bronzy to purplish in the spring. Becomes glossy dark green in summer. Undersides are gray-green to blue-green with hairs. Margins are entire with teeth near the apex. Bases are rounded. Non-showy fall color is yellowish-green.
  • Bark:
    Bark Color:
    Black
    Dark Brown
    Surface/Attachment:
    Ridges
    Bark Description:
    The bark is blackish-brown and smooth at first. It becomes furrowed and rough with age.
  • Stem:
    Stem Color:
    Green
    Stem Is Aromatic:
    No
    Stem Bud Terminal:
    Cluster of terminal buds
    Stem Bud Scales:
    Enclosed in more than 2 scales
    Stem Lenticels:
    Conspicuous
    Stem Surface:
    Smooth (glabrous)
    Stem Description:
    Stems are dark olive green, stiff, thick with pale lenticels. Buds are brown with scales.
  • Landscape:
    Landscape Location:
    Lawn
    Woodland
    Landscape Theme:
    Asian Garden
    Design Feature:
    Screen/Privacy
    Shade Tree
    Specimen
    Street Tree
    Resistance To Challenges:
    Deer
  • 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