Life history

Species overview

Butternut (Juglans cinerea), a Wisconsin Special Concern plant, is found in mesic hardwoods and riparian hardwood forests. Blooming occurs April to June; fruiting occurs October. The optimal identification period for this species is all year.

Synonyms: Wallia cinerea

Identification

• Distinguishing characteristics: Distinguished from other genera by chambered pith. Distinguished from J. nigra by leaves with terminal leaflet present and dense pad of hairs above leaf scar.
• Flower characteristics: Male catkins greenish, 8 to 12 cm long; female flowers in short spikes terminating branches, red, 4 to 7 cm long.
• Fruit characteristics: Ovoid nut approximately 6 cm long and with 2 to 4 longitudinal ridges.
• Leaf characteristics: Alternate, pinnately compound, 40 to 75 cm long and with 11 to 17 nearly sessile leaflets; terminal leaflet present.

Phenology

• Blooming phenology: April to June
• Fruiting phenology: October
• Optimum time to identify: The optimal identification period for this species is all year

Other

• Growth form: Tree
• Vegetative reproduction:
• Life cycle: Perennial
• Comments: Associated Species: Tilia americana, Ulmus americana, Acer saccharum, Quercus rubra, Claytonia virginiana, Solidago caesia.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - state and federal - and the rank (S and G Ranks) for Butternut (Juglans cinerea). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.

Habitats and landscapes

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

General habitat information

• Habitat description: Found in mesic hardwoods and riparian hardwood forests.
• Soils: Sandy loam soils.

Natural communities

This table lists the natural communities that are associated with Butternut. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).

Ecological landscapes

This table lists the ecological landscape association scores for Butternut. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.

Species guidance

The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.

Avoidance measures

These are specific actions designed to avoid "take" (mortality) of this species.

• Avoid locating landings, staging areas, or access routes on or near known populations.
• Avoid known individual plant locations and conduct operations elsewhere when they are least likely to cause damage. Ideally, this would involve frozen, snow-covered ground. However, in areas of the state where frozen conditions are unreliable, very dry soils late in the growing season might be the best available alternative. Consult with a biologist, if needed.
• Avoid broadcast spraying of herbicides; use care with spot spraying.

Management guidance

Management guidelines are additional considerations that may help maintain or enhance habitat for this species

• The primary threat to this species is a fungal disease called Butternut canker. If healthy individuals are observed in an area where the disease has already spread, please notify your local District Ecologist or NHI staff for specific recommendations. These individuals may provide important information on disease resistance and future conservation.
• Although maintaining high overall forest canopy is important, silvicultural techniques which open small gaps in the canopy may be beneficial to this species.

Other resources

Links to additional Butternut information

Other links related to vascular plants (all exit the DNR website)

• Wisconsin Flora
• NatureServe Explorer
• Atlas of Wisconsin Prairie and Savanna Flora - Wisconsin State Herbarium
• USDA - NRCS Plants Database
• USGS Midwestern Wetland Flora - field office guide to plant species
• eFloras
• Cofrin Center for Biodiversity Herbarium
• Intermountain Herbarium Grasses of North America
• Orchids of Wisconsin

Photos

Click to view a larger version. Please considering donating a photo to the Natural Heritage Conservation Program for educational uses. Photo use