Juglans cinerea (Butternut)

Plant Info
Also known as: White Walnut
Genus:Juglans
Family:Juglandaceae (Walnut)
Life cycle:perennial woody
Origin:native
Status:
  • State Endangered
Habitat:part shade, sun; average moisture; hardwood and mixed forest, river terraces, banks, swamps
Bloom season:May - June
Plant height:60 to 80 feet
Wetland Indicator Status:GP: none MW: FACU NCNE: FACU
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

Pick an image for a larger view. See the glossary for icon descriptions.

Detailed Information

Flower: Flower shape: indistinct Cluster type: spike

[photo of male catkins] Male and female flowers are borne separately on the same branch (monoecious). Male flowers are in clusters called catkins, 2 to 5½ inches long, pendulous in flower, single in the leaf axils of 1 year old branchlets, the flowers yellowish-green with up to 15 stamens per flower. Female flowers are in a short spike at the tip of this year's new branchlets with up to 7 flowers in the spike, the flowers with a stout, green ovary covered in sticky hairs and a pair of broad, spreading, red stigma at the top.

Leaves and bark: Leaf attachment: alternate Leaf attachment: whorl Leaf type: compound

[photo of leaves] Leaves are alternate, usually crowded at branch tips and appearing whorled, 1 to 2 feet long, compound with 11 to 17 leaflets. Leaflets are lance-oblong, 2 to 4½ inches long, 1 to 2 inches wide, finely toothed around the edges, with an abrupt taper to a pointed tip, asymmetrical and rounded to straight across at base, and very short-stalked. The upper surface is dark green and sparsely hairy, the lower is paler in color and covered in branched hairs, especially in the vein axils, and sometimes glandular-hairy. The compound leaf stalk is green and covered in sticky hairs.

[photo of twig and buds] Buds are light brown and covered in short fuzz, the terminal bud cone-shaped and slightly flattened. New twigs are green to olive-brown, variously covered in a mix of glandular and non-glandular hairs, becoming smooth the second year. Leaf scars are more or less T-shaped, straight to slightly convex across the top, often with a pad of dense hairs along the upper edge. Branch pith is chambered and dark brown.

[photo of smooth bark on young tree] Older bark is gray to gray-brown with scattered pale lenticels (pores), smooth but developing narrow, flat ridges and broader, shallow furrows with age. Trunks can reach up to 2 feet diameter at breast height (dbh).

Fruit: Fruit type: nut

[photo of fruit] Fruit is oval-elliptic, 1 to 3 inches long, longer than wide, the outer husk greenish with about 8 longitudinal ridges and densely covered in short, sticky hairs. Inside is a sweet nut with a hard shell. Fruits are usually in clusters of 3 to 5 at branch tips.

Notes:

Butternut was once a common forest species in the eastern half of North America, but throughout its range it's being ravaged by butternut canker, a fungal disease thought to be introduced in the 1960s though its exact origin is unknown. The disease manifests as black, open wounds in the bark of trunks, twigs and branches, and can be carried in the husks of fruit, killing any offspring of an infected mother tree. According to the DNR, it was first discovered in southeast Minnesota in the 1970s and has spread throughout the state. Listed as a Special Concern species in 1996, it was elevated to Endangered in 2013. Fortunately, a small percentage of trees appear to be immune so there is some hope of saving the species from extinction. Time will tell. Butternut closely resembles the related Black Walnut (Juglans nigra), which is distinguished by more spherical fruits that are single or in pairs, light brown pith in the twigs, the leaflet hairs are not branched, the terminal leaflet is either missing or much smaller than the lateral leaflets, and leaf scars are notched at the tip and lack the band of velvety hairs along the top edge. Black Walnut fruits can also stain your hands black, and broken twigs and crushed leaves give off a strong, pungent odor. Butternut does neither of these.

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More photos

Photos courtesy Peter M. Dziuk taken from various plantings in Minnesota. Juglans cinerea bark By Illustratedjc (Own work), via Wikimedia Commons, used under CC BY-SA 4.0

Comments

Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Kurt - West of Whitewater State Park
on: 2017-05-18 21:47:41

Healthy specimen found. About 16 inches in diameter. Abundant seedlings found below the tree.

Posted by: Kenny h - Lake Louise State Park
on: 2017-10-28 07:43:40

A friend showed me a stand of DEAD Butternuts...we want to replace these trees...KATY...ANYONE...where can we purchase canker resistant pure Butternut stock...available in Quebec...cant ship to USA???

Posted by: K. Chayka
on: 2017-10-28 09:40:03

You might contact the native plant nurseries, who may have more information on this.

Posted by: Kenny h - Lake Louise State Park
on: 2017-10-28 12:53:04

THANK YOU KATY!!!...talked on phone with both native nurseries I've dealt with in the past...Prairie Moon...Prairie Nursery Westfield Ws...both said not available...gave no other leads...i'm 63...time is of the essence...need to get these trees going...propigate via seeds/cuttings in future...we have to pay it forward.

Posted by: K. Chayka
on: 2017-10-28 17:21:21

I have some more bad news for you, Kenny. Thousand canker disease that is threatening to wipe out walnuts, too. Then there is oak wilt, which will wipe out all the oaks, plus many other threats to our native trees. I hate to be a pessimist, but it's a losing battle.

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