Black walnut Juglans nigra (F)
ABOUT
Juglans nigra, commonly known as the Black walnut, is a large deciduous tree that can grow up to 100 feet tall and 40-60 feet wide.
Its trunk is typically straight and can be up to 3 feet in diameter. The bark is dark gray and deeply furrowed, giving it a rugged appearance.
The leaves are alternate and compound, with 15-23 leaflets per leaf. Each leaflet is 2-4 inches long and 1-2 inches wide, and has a dark green, glossy upper surface and a lighter green lower surface.
The tree produces large, round, greenish-yellow fruits that are encased in a hard, spiky outer shell. The nuts inside the shell are edible, and are typically harvested in the fall.
About this plant
NamesFamily
Juglandaceae
Synonyms
Black walnut, American walnut, American black walnut, Eastern American black walnut, Eastern black walnut
ToxicityTo humans
Juglans nigra is not toxic to humans when consumed in normal amounts.
However, the green husks of the nuts contain a chemical called juglone which can cause skin irritation or allergic reactions in some people.
Ingesting large amounts of the leaves, bark, or nut husks can also cause stomach upset.To pets
Juglans nigra is not toxic to animals when consumed in normal amounts.
However, the green husks of the nuts contain a chemical called juglone which can be toxic to horses and other livestock if consumed in large amounts.
The tree's leaves, bark, and nut husks can also cause stomach upset if ingested in large amounts.
CharacteristicsLife cycle
Perennials
Foliage type
Deciduous
Color of leaves
Green
Flower color
Green
Height
Up to 100 feet
Spread
Up to 60 feet
Plant type
Tree
Hardiness zones
3
Native area
North America
Benefits
General BenefitsJuglans nigra produces edible nuts that are rich in protein, healthy fats, and various vitamins and minerals. They are commonly used in cooking and baking, and are also used to make oil, butter and flour;
Juglans nigra has an attractive appearance and can be used as a shade tree or as an ornamental tree in landscaping;
The tree is known to improve soil health by adding organic matter and increasing the soil's ability to hold water;
This plant provides food and shelter for a variety of wildlife species, including squirrels, birds, and deer;
Juglans nigra wood is hard, heavy and durable. It is used for furniture, flooring, and other woodworking projects.
Medical PropertiesThe nuts of Juglans nigra have anti-inflammatory properties, which can help to reduce pain and inflammation in the body;
The nuts of Juglans nigra are rich in antioxidants, which can help to protect the body against damage from free radicals;
Some studies suggest that Juglans nigra may have anti-cancer properties, although more research is needed to confirm this
Juglans nigra is rich in vitamins and minerals that can help to boost the immune system;
Juglans nigra may help to improve digestive health by preventing constipation and diarrhea.
It's important to consult with a specialist before using Juglans nigra for medicinal purposes, as it may interact with other medications or have negative side effects.
Other UsesThe hulls of black walnuts contain a dark brown dye that can be used to color fabrics and other materials;
The leaves and hulls of black walnuts contain compounds that are toxic to certain types of insects, and can be used to repel them when crushed and applied to the skin;
The walnuts of Juglans nigra are edible, and they can be used in a variety of dishes, as well as in the production of different products such as oil and flour;
The oil extracted from the black walnuts can be used in cosmetics and skin care products, due to its nourishing properties.
Interesting Facts
Plant SymbolismBlack walnut tree is often associated with strength, power and resilience. The tree's hard wood and deep roots can be seen as a symbol of determination and groundedness. The tree's nuts can symbolize abundance and fertility. The tree's leaves and bark can symbolize healing and protection.
It is important to note that symbolism can be personal and can vary between cultures, and that the specific symbolism of the Juglans nigra is not widely recognized.
WaterYoung trees need to be watered weekly, especially during dry periods. Once established, the tree can tolerate periods of drought and does not require frequent watering.
It is important to note that over-watering can also be harmful, as it can lead to root rot. It is important to check the soil moisture before watering and adjust watering schedule accordingly.
LightJuglans nigra is a shade-tolerant tree, but it prefers full sun to partial shade. It can grow well in areas that receive filtered sunlight or dappled shade.
TemperatureJuglans nigra can tolerate a wide range of temperatures and can grow in USDA hardiness zones 4-9. It can tolerate temperatures as low as -30°F and as high as 110°F.
The tree prefers temperatures between 60-75°F and it can grow in both cold and warm climates.
PruningPruning Juglans nigra is essential for maintaining its shape and size, as well as promoting healthy growth. Prune the tree in late winter or early spring, before new growth appears.
SoilJuglans nigra prefers well-draining, fertile soil with a pH range of 6.0-7.0.
The tree prefers a slightly acidic to neutral soil. It is important to ensure that the soil is well-draining, as Juglans nigra does not tolerate standing water.
Humidity & MistingJuglans nigra prefers moderate humidity levels, but can tolerate a wide range of humidity levels. It is not particularly sensitive to humidity, but it's important to keep in mind that high humidity can increase the risk of fungal diseases.
Suitable locationsIndoor
Not growing
Outdoor
Juglans nigra is a hardy and adaptable tree that can be grown outdoors in a wide range of conditions. It prefers full sun to partial shade, and can tolerate a wide range of temperatures. The tree is hardy in zones 4 and higher.
It prefers well-draining, fertile soil with a pH range of 6.0-7.0, a slightly acidic to neutral soil. It is important to ensure that the soil is well-draining, as Juglans nigra does not tolerate standing water. It needs moderate humidity levels, but can tolerate a wide range of humidity levels.Hardiness zone
USDA 4 - 10
Life cycleJuglans nigra seeds will germinate in the spring when the soil temperature reaches 60-65 degrees Fahrenheit. Germination typically takes place within 2-3 weeks.
After germination, the seedling stage begins. The seedling is a small plant with a single stem and a few leaves. It will continue to grow, developing new leaves and branching out, in this stage for the first two years.
During the juvenile stage, which typically lasts from 2-8 years, the tree will continue to grow and develop. It will develop a more defined trunk and branches, and will begin to produce nuts.
Once the tree reaches maturity, usually around 8-20 years, it will reach its full height and width. It will continue to produce nuts each year and will have a well-developed canopy.
As Juglans nigra reaches old age, usually around 100-150 years, it will begin to decline in health and productivity. The tree will produce fewer nuts, and branches and leaves may die back. Eventually, the tree will die and decompose, returning nutrients to the soil.
PropogationPropogation time
Spring - summer
By SEEDS:
The easiest and most common method of propagating the black walnut is through seed. The seeds should be collected in fall, when the tree's fruit or nut are ripe. The seeds should be stratified (kept in cold and moist conditions) before sowing to break the dormancy, usually for 90 days. Germination typically takes several weeks.
By GRAFTING:
Grafting is a method of propagating the black walnut by attaching a cutting from one tree to the rootstock of another. This method is typically done in late winter or early spring, when the tree is dormant.
By AIR LAYERING:
Air layering is a method of propagating the black walnut by rooting a stem while it is still attached to the parent tree. This method is typically done in late spring or early summer.
PestsAphid, Walnut caterpillar, Walnut husk fly, Walnut twig beetle
DiseasesAnthracnose, Crown gall, Canker, Walnut blight
