Black Walnut - Juglans nigra

Black Walnut

Juglans nigra

Black walnut leaves and bark are used in various medicinal preparations to treat parasitic worm infections, diphtheria, syphilis, skin infections, heart diseases, and diabetes.

  • Plant Family: Juglandaceae
  • Plant type: Perennial
  • Other names: Carya, Jupiter’s nuts
  • Medicinal: Yes
  • Culinary: No
  • Ceremonial: No
  • Parts Used: Leaves, Green Hull, Nuts & Bark
  • Side Effects: Don't use for more than two weeks at a time.
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About Black Walnut

Black Walnut is a rapidly growing deciduous tree that holds both medicinal and ornamental importance. Its trunk can stretch up to a height of 130 ft, holding grayish-black bark. It possesses pinnately compound leaves that are arranged in an alternate fashion on the stem. Being a monoecious plant, the black walnut produces staminate (male flowers) and pistillate (female flowers) on the same tree. 

The male flowers are dangling catkins while the female ones appear in the form of clusters of two or five. The fine wood obtained from black walnut trees is heavy and highly durable which makes it appropriate for making cabinets, furniture, gunstocks, veneer, airplane propellers, and ships. Due to the sweet taste of black walnut seeds, they were historically used in confectionery. 

Black walnut leaves and bark are used in various medicinal preparations to treat parasitic worm infections, diphtheria, syphilis, leukemia, skin infections, heart diseases, diabetes, and even cancer. 

Black walnut contains a host of medicinally active compounds, including linoleic acid, linolenic acid, palmitic acid, oleic acid, stearic acid, magnesium, potassium, and much more. It naturally contains juglone, an active phytoconstituent, that has proven to be toxic for certain plants in the vicinity of black walnut trees. It deprives the other plant of respiration due to which they eventually die and the black walnut tree gains all the nutrients for which it was competing before.



Walnut seeds require cold treatment before being subjected to the soil for germination. This can be done by either stratifying them indoors or planting the nuts outdoors during fall.  

It is recommended to start the black walnut plant outdoors in the fall as the indoor plant has to be transplanted in garden beds at some point to give it space for establishing a thick trunk and lavish canopy. 

Black Walnut requires fertile, moist but well-drained soil that can be sandy, loamy, or silty clay loam. It is intolerant of drought so it requires plenty of water to flourish.

Black walnut takes around four to six weeks to show germination. From then on, the black walnut plant grows rapidly, at the pace of 3 to 4 inches per year. Once established, it produces flowers in late spring, reflecting green and yellow shades.

As male and female flowers are produced separately on the same tree in walnut, they are wind-pollinated. The male flowers shed pollen when the stigma of female flowers is receptive. The female flower then transforms into a big gorgeous nut. This nut can be saved for starting a new plant or eaten raw to obtain its benefits.




Black walnuts can be harvested anytime during late September to early October when the outer is soft but green. 

Black walnut fruit (nut), hull (shell of the nut), and leaves can be harvested by hand simply or with a nut-gathering tool.

Carefully washed and dried Black walnuts should be stored in an airtight container in the refrigerator or freezer. This way, you can preserve the walnuts for over a year.


Black walnuts are used all around the world due to their amazing flavor and top-notch medicinal benefits.

  • Tincture - Black walnuts hulls are macerated in alcohol for 4 to 6 weeks in grain alcohol to make a black walnut tincture.
  • Tea -  Shelled black walnuts are added to a cup of hot boiling water to make black walnut tea.
  • Salve - Black walnut-infused oil is thickened with beeswax pastilles (and usually in combination with a few drops of lavender and clove essential oil) to formulate a salve.
  • Syrup - Black Walnut sap is collected and boiled over medium flame until it reaches a certain viscosity. According to farmers, 20 ounces of sap for 1 ounce of syrup creates a perfect golden syrup.
  • Infused oil - The outer green husks of the black walnuts are ground and added to the olive oil to infuse its goodness for 2 to 3 weeks on a sunny windowsill to formulate black walnut-infused oil. 


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