Although it is native to the northeastern United States, butternut (Juglans cinerea) is becoming more and more rare in the wild due to butternut canker, a vicious disease from which butternuts rarely recover. However, the butternut is a stately tree that produces delicious edible nuts after a decade or two. It is also known as the white walnut tree.
Of all the walnuts (Juglans spp.), butternut is the most cold hardy, growing well in U.S. Department of Agriculture plant hardiness zones 3 through 9. It is a tall tree, usually growing to between 40 and 60 feet. It also has a spread of 40 to 60 feet, giving it a rounded appearance. Butternut prefers moist, organically rich, well-drained soils. It will only grow in full sun and is difficult to transplant because of its long, easily damaged taproot. The nuts are rich and butter-flavored, to which their popularity is owed.
A butternut tree can be expected to reach reproductive maturity -- meaning that is capable of producing flowers and fruit -- at about 20 years of age. However, some trees reach maturity sooner and can begin producing fruit in as few as 10 years. Although butternut tree is not very long-lived, usually dying by the time it reaches 75 years or so, this still means it can produce nuts for upwards of 50 years.
Butternuts mature every year in the fall. Yellow-green flowers appear in spring, between April and June depending on the climate of its planting site. Because the tree is monoecious, male and female organs are contained in separate flowers. Once male flowers pollinate females, the fruit or nut begins to form. The nutshell is oval, longer than it is broad, and about 1 to 2 inches long. The green husk around the shell matures to brown in fall.
You can store butternuts a number of ways. After picking them, you must remove the husk or hull immediately to prevent it from retaining moisture and rotting. Spread the nuts in a single layer on a smooth, outdoor surface (if possible, depending on rain) until nuts are dry when you crack them open. In addition to being planted for its edible nuts, butternut is sometimes used as a landscape tree. If you are a proponent of native gardening and live in the Northeast, butternut tree is a good one to plant, as it is both native to the area and dwindling in the wild.
- University of Tennessee, Knoxville: Steps Toward Butternut (Juglans Cinerea L.) Restoration
- Miami University: White Walnut
- Missouri Botanical Garden: Juglans Cinerea
- University of New Hampshire Cooperative Extension: Big Tree of the Month -- Butternut (Juglans Cinerea)
- University of California Division of Agriculture and Natural Resources: Harvesting and Storing Your Home Orchard’s Nut Crop: Almonds, Walnuts, Pecans, Pistachios, and Chestnuts