Prefers moist, organically rich, well-drained soils in full sun. Intolerant of shade. Difficult to transplant because of deep taproot.
Although not commonly grown as an ornamental, butternut is a valued native American tree that is unfortunately becoming increasingly rare in the wild now because of a canker disease (see below). Butternut is similar in appearance to black walnut (see Juglans nigra), except it is generally smaller, its bark is less fissured, it has fewer leaflets per leaf and its nuts are more oval than round. It is native to moist bottomlands, lowland forests and some drier limestone soils in eastern and midwestern North America, from New Brunswick to Minnesota, south to Georgia and Arkansas. In Missouri, it typically occurs in rich woods and along streams in all but the far western parts of the state. It is a deciduous tree that typically grows 40-60’ (less frequently to 100’) tall with an open broadly-rounded crown. Features odd-pinnate compound leaves (to 20” long), each with 11-17 oblong to lanceolate leaflets. Foliage turns an undistinguished yellow in fall. Yellowish green monoecious flowers appear in late spring (May-June), the male flowers in drooping catkins and the female flowers in short terminal spikes. Female flowers give way to clusters of edible oval nuts encased in hairy indehiscent husks. Nuts mature in fall. Nut shells can be hard to crack and the kernels are often small. But the kernels are sweet, oily and tasty, having a buttery flavor as per the common name. Native Americans used the nuts for food and boiled the tree sap for syrup. Butternut wood, though softer than black walnut, was once valued for a variety of uses including paneling, cabinets and furniture. Overharvesting of trees for commercial use plus losses from the canker disease have reduced native tree populations to the point where the butternut is now endangered in most parts of its range. Juglans comes from the Latin words jovis and glans meaning nut of Jove. Cinerea refers to the ash gray color of the bark. This species is sometimes commonly called white walnut because of the light color of the wood.
Susceptible to butternut dieback or butternut canker (Sirococcus clavigignenti-juglandacearum), which is a usually fatal fungal disease that is devastating butternut trees in the wild. Onset of the disease is often first seen as dying stems and branches in the upper crown. This canker has no cure. Insect pests include butternut curculio, borers, lace bugs, caterpillars and bark beetles. As with black walnut, butternut roots produce chemicals called juglones which are very toxic to certain other plants such as azaleas, rhododendrons, blueberries, peonies and solanaceous crops (tomatoes, peppers, potatoes). Most of the toxicity is limited to within the drip line of the tree, but the area of toxicity typically increases outward as the tree matures.
Butternut is of interest to native plant enthusiasts and for those who wish to harvest the nuts. It is otherwise infrequently planted as an ornamental tree.