By Kathleen Cue, Nebraska Extension Horticulture Educator in Dodge County (Week of November 8, 2021)
Urban dwellers either praise or curse the black walnut (Juglans nigra). Some find the tree troublesome because of the nuts they drop, the juglone (a natural herbicide) secreted into the soil to kill nearby plants, and the increased number of squirrels in the neighborhood. Supporters of black walnut like the tree because it is native, well adapted to the precipitation and temperature variations of Midwest weather, is stately, grows valuable wood and nuts, and provides food for wildlife.
No woodworker’s material commands higher values than black walnut. It is not unusual for people with a bit of underutilized land to grow walnut trees, referring to the eventual sale of the trees as their “retirement fund”. It turns out that black walnut rustling is a thing, with thieves cutting down trees on public and private lands, sometimes in broad daylight, to sell to lumber mills. Theft, unfortunately, centers on the stately older trees.
Both the husks and hulls of black walnut are used to make stains for baskets and wood. Interestingly, the wood of black walnut is already a dark rich brown and requires no stain.
Nuts of black walnut are delicious and nutritious but if you’ve ever husked and cracked a black walnut, only to be confronted by multiple chambers inside, you’ll know the tedium involved in getting the nutmeats out. Consider growing one of the newer cultivars trialed by UNL’s Professor emeritus Dr. Bill Gustafson and available through the Nebraska Nut Growers Association (nebraskanutgrowers.org). These newer varieties have just two chambers inside the nut, making it possible to remove the nut in two large chunks.
A black walnut problem causing tree mortality, thousand canker disease (TCD), has foresters and tree pathologists monitoring its spread. This is a disease complex, combining feeding by the walnut twig beetle (Pityophthorus juglandis) with the canker-forming fungal pathogen Geosmithia morbida. The walnut twig beetle carries the fungal pathogen, unintentionally inoculating trees as it feeds. The Nebraska Department of Agriculture enacted an exterior state quarantine of walnut in 2010 and presently, thousand canker disease has not been found in Nebraska. More information about TCD can be found here: USDA APHIS | Thousand Cankers Disease .