In total 56 new butternut observations, 45 of which were verified to research grade, were reported to iNaturalist from July 1 through December 31, 2022. This represents a 67% increase in research grade iNaturalist reports of butternuts in Minnesota during the project period. 

• 45 new research grade reports in iNaturalist, several of which show “healthy” bark

• 36 unique observers

• 23 unique identifiers (We learned there are others very interested in butternut!)

• 11 observations did not provide enough information to verify

Report mostly healthy (see below for details) butternut trees to iNaturalist. Be sure to mark them as "Butternut Juglans cinerea" unless you think they are hybrids. If you think they may be hybrids mark them as "Bixby's Walnut Juglans × bixbyi". We really only want butternut, but understand the hybrids and native butternuts can be very hard to distinguish. Our experts will confirm identification in iNaturalist or follow-up with the reporter if needed.

We'll need as many good pictures as you can upload to iNaturalist, likely 4, see specific directions for what type of pictures in the "Assessing and recording butternut health" section below. In addition we need accurate location information and the date, both basic features of iNat reports. If the tree is a yard or community tree be sure to toggle over the cultivate choice at the bottom of the iNat report.

Butternut identification is complicated because it hybridizes easily with Japanese walnut (Juglans ailanthifolia) and heartnut, a Japanese walnut cultivar, which are both sold in trade and are highly resistant to butternut canker.

Purdue University has a great online resource: Identification of Butternuts and Butternut Hybrids to help sort out identification.  

Photo: Paul Wray, Iowa State University, Bugwood.org