Description & Overview

Butternut is a native Wisconsinite that belongs to the walnut family. In spring, female flower spikes are fertilized by male catkins, eventually producing an oblong nut with a buttery flavor, encased in a sticky, hairy husk, hence the common name of “Butternut.” The leaves are similar to a Black Walnut in that they are pinnately compound, but Butternut leaflets are smaller and there are fewer of them. In the fall they turn a bright yellow. The grey bark is distinctive enough that this tree can be identified even in the dead of winter as the mature bark is made up of vertical, long, narrow plates.

You may also know Butternut as White Walnut or Oilnut.

Core Characteristics

Category: Tree

Wisconsin Native: Yes

USDA Hardiness Zone: to zone 3

Mature Height: 40-60 feet

Mature Spread: 40-60 feet

Growth Rate: Slow

Growth Form: Tall, spreading

Light Requirements: Full Sun

Site Requirements: Moist, rich, deep soils. Drought tolerant once established.

Flower: Yellow/green, monoecious

Bloom Period: Late Spring

Foliage: Dark green. Pinnately compound with 11 - 17 leaflets.

Fall Color: Yellow

Urban Approved: Yes

Fruit Notes: Nut, edible. 1.5 - 2.2" maturing in Fall

Suggested Uses

Butternut favors low woodlands where it grows on sunny slopes and hillsides along streams in loamy, moist, well-draining soil. It is also found on calcareous soils on rocky slopes and terraces. Butternut can tolerate drought but will flounder in nutrient-poor, compact soil.

Butternut cannot tolerate competition from above, as the shade will soon kill it. It is often found as a party of one in woodlands where there is enough clear space to provide exposure to full sun through to maturity. The fight for light, water, nutrients, and space drives some plants to extremes to preserve themselves. In the case of Butternuts, they are allelopathic exuding a toxic chemical called jug lone, mainly concentrated in the roots, which will outcompete many juglone-sensitive species, including other Butternut saplings.

Butternut is seldom used as a landscape tree. This is likely due to a few factors. First, many do not want the nuts in their yard, which once they fall, become litter to someone who enjoys a manicured yard. Another is the landscaping limit imposed by juglone, as some plant species are juglone-sensitive, though this is a larger issue with Black Walnut, which, as Butternut’s big brother, does create juglone in higher concentrations.

Conservation/Diversity/Naturalization: This is a species of Special Concern in Wisconsin due to a decline in national and local populations caused by Butternut canker, which is often fatal. The best thing to do is to plant more and not disturb healthy individuals. If you are interested in native species and are concerned about whose numbers are dwindling, consider saving space on your property for a Butternut, a tree that holds value for so much wildlife. At Johnson’s Nursery, we select our nuts for propagating Butternut from trees that seem to be resistant to the canker, however; that doesn’t guarantee any immunity or resistance. Our hope is that land managers and people that go nuts for nut trees will continue to plant them and keep the species going. Often the trees will be of high wildlife value for 25 to 35 years before the canker can take its toll.

Butternut is a native Wisconsinite that belongs to the walnut family. In spring, female flower spikes are fertilized by male catkins, eventually produ…

Wildlife Value

Butternuts are sweet and oily and prized by humans and wildlife.

The nuts are eaten by myriad mammals, birds, and rodents. They are mainly dispersed by squirrels as well as other rodents that may cache the nuts for winter.

Butternut is a larval host to the Luna Moth and the Butternut Woolyworm, the larvae of a sawfly.

Maintenance Tips

Any dead stems, or any stems showing signs of disease, can be pruned in late winter/early spring.

As a nut-producing tree, site this tree away from areas where vehicles will be parked, lawnmowers will be driven, or where people will play Thanksgiving Day backyard football. Thinking of this BEFORE the tree is planted will prevent the frustration some homeowners face when they happen to simply inherit a tree that drops large nuts by their front door.

Pests/Problems

Black Walnut Tolerant: Yes
Deer Resistant: Unknown
Rabbit Resistant: Yes

Roots, leaves, and husks of Butternut exude a chemical called juglone. Keep this in mind when choosing companion plants for your landscape as some do exhibit sensitivity to this chemical. We recommend reading our Black Walnut Toxicity article to learn more about juglone.
Butternut grows easily but is tricky to transplant due to a deep taproot. Best to leave it be.

Butternut curculio (Conotrachelus juglandis), is a weevil whose juveniles and adults feed on young stems, leaves, and nuts, injuring the tree and impacting the nut crop. Weevils, bark beetles, lace bugs, wood borers, and caterpillars will feed on various parts of the tree. The damage made by these insects is largely cosmetic.

Butternut canker is caused by the Sirococcus clavigignenti-juglandacearum fungus that causes cankers to grow along stems in the canopy. Enough cankers will girdle and kill a stem or a branch. When the disease has progressed to girdle the trunk the tree dies. Butternut canker has caused the near eradication of Butternut in North Carolina and South Carolina, where trees do not root-sprout. It is listed as endangered in Minnesota and a species of Special Concern in Wisconsin. It is generally believed that all Butternut trees are infected with Butternut Canker, sometimes also called Butternut Blight. Some trees are highly susceptible and die within a few years of showing signs. There is no cure. Other trees are certainly more resistant, however, Butternut can survive well into maturity to produce nuts, feed wildlife, and propagate. These are the trees whose nuts we can use to plant more Butternut!

In some areas, healthy and presumably resistant trees have been found growing adjacent to diseased trees. These trees, if they are truly resistant, could be extremely valuable in efforts to preserve the species, and they must not be cut down. Cuttings and seeds taken from disease-resistant trees and propagated in tree plantations could potentially provide stock for landscaping purposes and possibly for reestablishing wild populations. It is also advisable to consider augmenting existing populations by direct planting of seeds taken from healthy trees.

Leaf Lore

Although Butternut is sometimes used in cabinetry and for furniture, it is mostly valued for its nuts. Cultivars have been bred to create varieties that produce nuts that are easier to crack. In New England, the nut is used to make Butternut-Maple candies. Trees can start to produce nuts in as many as 20 years.

Wisconsin was once one of the leading Butternut timber producers. The wood is lighter than Black Walnut, and due to their close relation, Butternut was also called White Walnut in the past. Butternut occurs farther north than Black Walnut and though they coexist in the middle of their range, Black Walnut occurs farther south. Both species are in the genus Juglans, and both produce the chemical juglone, though Black Walnut produces it in higher concentrations.

Native Americans ate the nuts and used them for their oil. The sap was used to make syrup. Orange dye was made from the nut’s outer covering.

During the Civil War, confederate troops used the husks of the butternuts to dye their uniforms.

Though known to live about 75 years on average, the oldest Butternut found in Minnesota was a whopping 221 years old!

Companion Plants

Butternut is found in Wisconsin forests among Basswood, Black Cherry, American Beech, Black Walnut, Hemlock, Shagbark Hickory, Oaks, Maples, Eastern White Pine, and Yellow and Sweet Birch.

Pagoda Dogwood, Witchhazel, Elderberry, Bladdernut, Wild Ginger, Spikenard, Solomon’s Seal, and Zig Zag Goldenrod can all happily live in the understory of this juglone-producing tree.

Butternut is a native Wisconsinite that belongs to the walnut family. In spring, female flower spikes are fertilized by male catkins, eventually produ…
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Written by Julia Feltes