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Oaks Quercus nigra

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

Water oak is native medium sized fast growing deciduous tree; however, sometimes it is considered an evergreen in the deep south. It is a member of the red oak group. It usually grows to a height of 50 to 80 feet tall and 50 to 70 feet wide. It has a conical to broad, rounded habit with a trunk diameter of 3.5 feet. The water oak is regarded as weaker wooded in comparison to most oaks, and it also has a shorter life span. It may only live 30 to 50 years. It is a member of the Fagaceae or beech family.

The water oak is native to the central and eastern United States.  It is found in forests, flood plains, and along rivers and streams or in sloped areas with drier soils. It is commonly found in the Coastal Plains and Piedmont areas of North Carolina in bottomland forests.

This tree prefers rich, medium to wet acidic soils in full sun. It is adaptable to other soil types and part shade. The water oak transplants easily and adapts well to wet sites. 

The leaves of the water oak are bluish green, spatulate, or variable in shape and may have 0 to 5 lobes. The margins may be entire, or bristle tipped. The male flowers are cylindrical catkins, and the female flowers are short spikes. The fruit is an acorn that has a cup with wooly scales. It requires two growing seasons for the acorns to reach maturity.

The water oak is a risk for breakage from wind or ice. Other oaks such as the red oak, white oak, and swamp white oak have stronger branch structure and should be considered as an alternative. The water oak is similar to the willow oak in tree form and bark description, but the leaves are distinctly different.

The water oak is a great tree for naturalized areas, street tree or shade tree in large areas. It is particularly useful for low spots or moist areas in the landscape.

Seasons of Interest:

Bark:  Winter    Foliage:  Summer and Fall       Fruits: Fall

Quick ID Hints:

  • brown and smooth bark when the tree is young, gray black, furrowed, and rough with age
  • stems are slender, thin, and reddish-brown.
  • leaves are bluish- green on surface, paler beneath, spatulate, lanceolate, or variable in shape and may have 0 to 5 lobes.
  • alternate leaves with smooth or bristle-tipped margins
  • male flowers are drooping catkins, and female flowers appear as short spikes
  • fruit is an 1/2 to 1-inch nearly black acorn with a flat, scaled cap that covers about 1/3 of the nut.

Insects, Diseases and Other Plant Problems:  Oaks are susceptible to many diseases. The water oak is susceptible to oak wilt, often with fatal consequences. Other less serious diseases include chestnut blight, shoestring root rot, anthracnose, oak leaf blister, cankers, leaf spots, and powdery mildew. Scale, oak skeletonizer, leaf miners, galls, oak lace bugs, borers, caterpillars and nut weevils are potential insect pests. Chlorosis can occur if the pH level is too high and results in iron deficiency. Limbs are notoriously weak and at risk for breakage particularly in high winds or during winter snow and ice storms. 

VIDEO created by Andy Pulte for “Landscape Plant Identification, Taxonomy and Morphology” a plant identification course offered by the Department of Plant Sciences, University of Tennessee.

Profile Video:
See this plant in the following landscape:
Juniper Level Botanic Gardens: Front Shade Garden
Cultivars / Varieties:
Tags:
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Cultivars / Varieties:
Tags:
#showy flowers#deciduous#shade tree#full sun tolerant#wildlife plant#native tree#moths#yellow flowers#salt tolerant#showy leaves#broadleaf evergreen#cover plant#spring flowers#fall interest#flowering tree#street tree#showy fruits#small mammals#moist soil#food source wildlife#fast growing#cpp#fire low flammability#NC native#well-drained soil#deer resistant#acorns#nighttime garden#small and large mammals#children's garden#playground plant#weak wood#edible fruits#spring interest#acidic soils tolerant#pollinator plant#Braham Arboretum#fantz#compaction tolerant#larval host plant#deciduous tree#food source fall#food source herbage#Coastal FAC#Piedmont Mountains FAC#fall color yellow#sandy soils tolerant#wet soils tolerant#clay soils tolerant#bird friendly#food source hard mast fruit#mammals#fall color red#butterfly friendly#moth larvae#fall color bronze#fruits early fall#partial shade tolerant#problem for horses#Audubon#wind damage prone#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:
    nigra
    Family:
    Fagaceae
    Uses (Ethnobotany):
    Used as timber, fuel, veneer, and plywood but it is not good for finished lumber as it splits when drying. In the case of the Native Americans, this tree was also used for food and medicine.
    Life Cycle:
    Perennial
    Woody
    Recommended Propagation Strategy:
    Seed
    Stem Cutting
    Country Or Region Of Origin:
    Central & Eastern U.S.A
    Distribution:
    Native: United States--Al, AR, DE, FL, GA, KY, LA, MD, MS, MO, NJ, NC, OK, SC, TN, TX, and VA
    Fire Risk Rating:
    low flammability
    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. Acorns are eaten by woodpeckers, blue jays, ducks, small mammals, wild turkeys, white-tailed deer, and black bears.
    Play Value:
    Attracts Pollinators
    Edible fruit
    Wildlife Food Source
    Wildlife Nesting
    Edibility:
    Acorns (nuts) are edible after tannins are leached or boiled out
    Dimensions:
    Height: 50 ft. 0 in. - 80 ft. 0 in.
    Width: 50 ft. 0 in. - 70 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Native Plant
    Poisonous
    Tree
    Woody Plant Leaf Characteristics:
    Broadleaf Evergreen
    Deciduous
    Habit/Form:
    Conical
    Rounded
    Spreading
    Growth Rate:
    Rapid
    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)
    Soil Drainage:
    Good Drainage
    Moist
    Occasionally Dry
    Occasionally Wet
    Available Space To Plant:
    more than 60 feet
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    6b, 6a, 7b, 7a, 8b, 8a, 9b, 9a
  • Fruit:
    Fruit Color:
    Black
    Brown/Copper
    Fruit Value To Gardener:
    Edible
    Display/Harvest Time:
    Fall
    Fruit Type:
    Nut
    Fruit Length:
    < 1 inch
    Fruit Width:
    < 1 inch
    Fruit Description:
    The fruit is an 1/2 to 1-inch nearly black acorn with a flat, scaled cap that covers about 1/3 the nut. The acorn requires two growing seasons to reach maturity. Involucral bracts are in shallow cups and are imbricated. In North Carolina, the acorns are available from September to November.
  • Flowers:
    Flower Color:
    Gold/Yellow
    Green
    Flower Inflorescence:
    Catkin
    Insignificant
    Flower Bloom Time:
    Spring
    Flower Description:
    Male flowers in drooping catkins and female flowers in spikes. In North Carolina, flowers are available in the month of April.
  • Leaves:
    Woody Plant Leaf Characteristics:
    Broadleaf Evergreen
    Deciduous
    Leaf Color:
    Blue
    Green
    Leaf Value To Gardener:
    Showy
    Deciduous Leaf Fall Color:
    Brown/Copper
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Leaf Shape:
    Obovate
    Spatulate
    Leaf Margin:
    Entire
    Lobed
    Hairs Present:
    Yes
    Leaf Length:
    3-6 inches
    Leaf Width:
    1-3 inches
    Leaf Description:
    The leaves are 2 to 4 inches long and 1 to 2 inches wide, bluish green on the upper surface and appear paler and hairy on the undersides. They are alternate, simple, narrowly obovate to spatulate, the apex is shallowly 3-lobed or no lobes, lobes are bristle-tipped to lacking bristles, the base is long and tapering from the middle of the leaf, they are entire and sub coriaceous. The midrib has two conspicuous spreading lateral veins where the leaf broadens, bearing pubescent tuft in axils. Leaves may persist throughout the winter in zones 8 and 9.
  • Bark:
    Bark Color:
    Dark Brown
    Red/Burgundy
    Surface/Attachment:
    Ridges
    Scaly
    Bark Description:
    The bark is brown and smooth when the tree is young. As the tree ages it becomes gray black, furrowed, and rough.
  • Stem:
    Stem Color:
    Brown/Copper
    Red/Burgundy
    Stem Is Aromatic:
    No
    Stem Buds:
    Smooth/Hairless
    Stem Bud Terminal:
    Cluster of terminal buds
    Stem Form:
    Straight
    Stem Description:
    The stems are slender, thin, and reddish-brown. The bud are ovoid, 1/4" long, angled above and pointed, scales imbricate, and brown.
  • Landscape:
    Landscape Location:
    Lawn
    Naturalized Area
    Pond
    Recreational Play Area
    Riparian
    Landscape Theme:
    Butterfly Garden
    Children's Garden
    Native Garden
    Nighttime Garden
    Pollinator Garden
    Rain Garden
    Design Feature:
    Shade Tree
    Street Tree
    Attracts:
    Butterflies
    Moths
    Pollinators
    Small Mammals
    Songbirds
    Resistance To Challenges:
    Compaction
    Deer
    Drought
    Fire
    Pollution
    Salt
    Wet Soil
    Problems:
    Problem for Horses
    Weak Wood
  • Poisonous to Humans:
    Poison Severity:
    Low
    Poison Symptoms:
    Abdominal pain, constipation then diarrhea (occasionally bloody), depression, frequent urination, discolored urine, jaundice; acorns can obstruct the digestive tract
    Poison Toxic Principle:
    Gallotannins, quercitrin, and quercitin.
    Causes Contact Dermatitis:
    No
    Poison Part:
    Fruits
    Leaves