Keep in mind that black walnut trees don’t grow walnuts until they’re 4 to 7 years old. Butternuts take 2 to 3 years and English walnuts can take anywhere from 4 to 10 years. The most bountiful harvests usually occur after the tree (any variety) is 10 years old. The walnuts of English and black walnut trees are round while butternuts have oblong, papaya-shaped fruits. You may need to use binoculars since walnut trees can grow to be 50 to 100 feet (15 to 30 meters) tall and grow plumage high on their trunks.
If you remove a little of the gray outer bark from the trunk of a black walnut or English walnut tree, you’ll see a rich chocolate brown color underneath. The bark of black walnut trees can vary from dark brown to gray while butternuts have white-gray colored bark. This is a good way to identify walnut trees in the winter when they’re not producing walnuts and their leaves have dropped.
Butternut and English walnut trees also release toxins but in much smaller quantities so that other nearby trees and shrubs can survive. However, there are some trees that can tolerate the black walnut’s toxicity (note that this isn’t an exhaustive list): Japanese maple, red maple, yellow birch, redbud, sycamore, oak (all varieties), black cherry, willow, and elm.
Note that you’re less likely to find cracked shell in the winter when the tree is dormant.
The shell of English walnuts is thinner and much easier to crack open than the other 2 varieties. The walnuts you’re most likely to find in stores are typically from English walnut trees. Walnuts from black walnut trees are so strong they’re typically used to make flavorings and extracts. Be mindful of breaking open the husk from a black walnut tree because it can stain your hands and clothing.
The leaves of walnut trees typically appear later in the spring than other trees and drop sooner during late summer or early fall. This applies to English, butternut, and black walnut trees.
The largest leaflets can be found near the center of the twig. The leaflets will be slightly longer on butternut trees. English walnut trees have fewer leaflets than both butternut and black walnut trees (which have the most). The black walnut trees have compound leaves that occur alternately along the stems and are over a foot long, with around 23 leaves.
Due to the way they gray, the leaves may have a feathered look to them.
Sometimes black walnuts won’t grow terminal leaflets at all. Instead, they may have a small, fuzzy stub at the end of the rachis.
The twigs of every variety of walnut tree have chambered piths. English and black walnut trees will have dark brown pith while butternut trees are light tan inside the twigs.
Some people say the smell is reminiscent of store-bought furniture polish. If your nose picks up a pungent odor, it’s a good sign that it is a black walnut tree, as their leaves have a distinct smell.
