History: Native to much of the eastern and central United States and southern Ontario, Black Walnut has long been used as a source of food, dye, lovely dark wood, and as an ornamental tree. Although it is said to have a better flavour than the English walnut, the Black walnut remains less popular due to the increased difficulty of harvesting the nut meat from within the husk. Black walnut is also infamous for being allelopathic, meaning it secretes toxic chemicals (juglones) into the soil to reduce plant competition.
Why We Grow It: Black walnut is a beautiful tree that produces nuts with a stronger flavour than that of English walnuts. The sap can be boiled to make walnut syrup, which tastes very similar to maple syrup but with notes of caramel and butterscotch. Be mindful of the juglones in the in the roots/nut husks, they are toxic to many other species. They require a buffer of about 50'/30m from the edge of the trees canopy for juglone-sensitive plants. This article from PennState Extension has a helpful list of plants that tolerate juglones.
Canadian Hardiness Zone: 4
Soil Preference: Prefers loam but adaptable to different soil types
Growth Habits and Disease Resistance: Tree reaches 30-40m tall, tends to grow tall and straight when shaded by other trees and short and wide when not shaded. Susceptible to European canker and have numerous insect pests.
Sun/Shade: Full sun (approx. 8-10 hours of sun daily)
Pollination:Self-pollinating, this tree will produce nuts without a different Black Walnut tree present but will produce more and better nuts if one is present
Ripens: March for syrup, October for nuts
Storage:Nuts keep up to three months in the fridge, syrup can be stored for about a year in the pantry
Recommended Use: Nuts used for fresh eating, cooking or baking, or syrup enjoyed as you would maple syrup.
Height not including roots: 30cm+ one year seedling