The leaves of Juglans cinerea are alternate and compound with more than 9 leaflets, each toothed and wider than one cm. The chambered pith is a good character to help distinguish this genus in our area, and the leaf scar with a band of hairs above the top edge will help to distinguish Butternut from the similar Black Walnut (Juglans nigra).The fruit of Butternut is clearly longer than wide, compared to the fruit of Black Walnut which is roughly spherical. Butternut leaves are often densely hairy beneath with stellate hairs (branched hairs). Black walnut is much less hairy and the hairs are simple (not branched).

Butternut is found over most of Wisconsin except for the northernmost counties. It will not tolerate much shade (but may reach the canopy if it gets started in an opening) and is usually not abundant in any forests. Both Juglans species produce a substance in roots, fruit husks and leaves that is toxic (allelopathic) to some plant species, and strongly inhibits the growth of seedlings, including their own.