Plantae > Tracheophyta > Magnoliopsida > Fagales > Juglandaceae > Juglans > Juglans nigra

Juglans nigra (black walnut)

Synonyms: Juglans pitteursii; Wallia nigra

Wikipedia Abstract

Juglans nigra, the eastern black walnut, is a species of deciduous tree in the walnut family, Juglandaceae, native to eastern North America. It grows mostly in riparian zones, from southern Ontario, west to southeast South Dakota, south to Georgia, northern Florida and southwest to central Texas. Wild trees in the upper Ottawa Valley may be an isolated native population or may have derived from planted trees.
View Wikipedia Record: Juglans nigra


Air Quality Improvement [1]  Low
Allergen Potential [1]  High
Carbon Capture [1]  Medium-High
Screening - Summer [2]  Porous
Screening - Winter [2]  Porous
Shade Percentage [1]  91 %
Temperature Reduction [1]  Medium-High
Wind Reduction [1]  Medium
Bloom Period [2]  Late Spring
Drought Tolerance [2]  Low
Edible [3]  May be edible. See the Plants For A Future link below for details.
Fire Tolerance [2]  High
Flower Type [3]  Monoecious
Frost Free Days [2]  5 months 20 days
Fruit/Seed Abundance [2]  Low
Fruit/Seed Begin [2]  Fall
Fruit/Seed End [2]  Fall
Growth Form [2]  Single Stem
Growth Period [2]  Spring
Growth Rate [2]  Rapid
Hazards [3]  The plant has occasionally been known to cause contact dermatitis in humans;
Janka Hardness [4]  1010 lbf (458 kgf) Soft
Leaf Type [3]  Deciduous
Lifespan [2]  Perennial
Pollinators [3]  Wind
Propagation [2]  Bare Root, Container, Cutting, Seed
Root Depth [2]  3.346 feet (102 cm)
Scent [3]  The bruised leaves have a pleasant sweet though resinous smell.
Seed Spread Rate [2]  Slow
Seed Vigor [2]  High
Seeds Per [2]  40 / lb (88 / kg)
Shape/Orientation [2]  Erect
Specific Gravity [5]  0.55
Structure [3]  Tree
Usage [3]  A brown dye is obtained from the nuts, husks and bark; It does not require a mordant; The husks can be dried for later use; A brown dye is obtained from the leaves and stems; It does not require a mordant; The dye turns black if it is prepared in an iron pot; The leaves can be dried for later use; The husks are rich in tannin; The green fruit husks can be boiled to provide a yellow dye; The husks can be made into a high quality coal (does the report mean charcoal?; It was used in gas masks; The woody shells on the fruits have been used to make jewellery; Insects are said to avoid the walnut tree, hence it is often used as a poor man's insect repellent. When rubbed on faces, walnut leaves are said to repel flies; The leaves repel fleas and have been used as a strewing herb; They are also used as an insecticide against bed bugs; The ground up husks are also insecticidal; The leaves produce substances that depress the growth of other plants. These substances are washed onto the ground by rain and inhibit the growth of plants beneath the tree; The roots also produce substances that are toxic to many plant species, especially apples (Malus species), members of the Ericaceae, Potentilla spp and the white pines (certain Pinus spp.); An alternative ingredient of 'QR' herbal compost activator; This is a dried and powdered mixture of several herbs that can be added to a compost heap in order to speed up bacterial activity and thus shorten the time needed to make the compost; Wood - very ornamental, heavy, hard, strong, close-grained, very durable. Easily worked, it glues well, does not warp, shrink or swell much and takes a good polish. It weighs 38lb per cubic foot. A very valuable timber tree and possibly the most sought after wood in N. America, it is used in cabinet making, the interior finishes of houses, furniture, airplanes, ship building, veneer etc;
Vegetative Spread Rate [2]  None
Flower Color [2]  Yellow
Foliage Color [2]  Green
Fruit Color [2]  Brown
Fruit Conspicuous [2]  Yes
Height [3]  98 feet (30 m)
Width [3]  66 feet (20 m)
Hardiness Zone Minimum [1]  USDA Zone: 4 Low Temperature: -30 F° (-34.4 C°) → -20 F° (-28.9 C°)
Hardiness Zone Maximum [1]  USDA Zone: 9 Low Temperature: 20 F° (-6.7 C°) → 30 F° (-1.1 C°)
Light Preference [2]  Full Sun
Soil Acidity [2]  Neutral
Soil Fertility [2]  Very Rich
Water Use [1]  Moderate
View Plants For A Future Record : Juglans nigra

Protected Areas


Range Map


North America;

External References

USDA Plant Profile



Attributes / relations provided by
1i-Tree Species v. 4.0, developed by the USDA Forest Service's Northern Research Station and SUNY-ESF using the Horticopia, Inc. plant database.
2USDA Plants Database, U. S. Department of Agriculture
3Plants For A Future licensed under a Creative Commons License
4Wood Janka Hardness Scale/Chart J W Morlan's Unique Wood Gifts
5Forest Inventory and Analysis DB version 5.1, May 4, 2013, U.S. Forest Service
6HOSTS - a Database of the World's Lepidopteran Hostplants Gaden S. Robinson, Phillip R. Ackery, Ian J. Kitching, George W. Beccaloni AND Luis M. Hernández
7Ben-Dov, Y., Miller, D.R. & Gibson, G.A.P. ScaleNet 4 November 2009
8New Zealand Institute for Plant & Food Research Plant-SyNZ™ database
9Biological Records Centre Database of Insects and their Food Plants
10Geographic variation in walnut seed size correlates with hoarding behaviour of two rodent species, N. Tamura and F. Hayashi, Ecol Res (2008) 23: 607–614
Protected Areas provided by Biological Inventories of the World's Protected Areas in cooperation between the Information Center for the Environment at the University of California, Davis and numerous collaborators.
Calvin College Ecosystem Preserve
Edwin S. George Reserve, University of Michigan, Department of Ecology and Evolutionary Biology
Maher Sanctuary, Grand Rapids Audubon Club
Western Michigan University’s Asylum Lake
Abstract provided by DBpedia licensed under a Creative Commons License