If you are an avid arborist or if you live in an area that was until recently populated by native black walnut trees, you may have questions about how to plant a black walnut tree. Also, what other black walnut tree info can we dig up?
Black Walnut Tree Info
Black walnut trees are native to the central and eastern United States and until the turn of the century, quite common. These trees can live to up to 200 years of age and are one of six walnut species found in the United States. In a natural setting, black walnut trees can be found growing alongside:
Intolerant of drought, black walnut trees have a lovely canopy, stretching up to 100 feet in height. Valued for their lumber, walnuts also provide food and shelter for native wildlife.
Black walnut roots, however, contain juglone which may be toxic to some types of plants. Be aware of this and plan accordingly.
The fruit husks from black walnut are used to make a yellow dye and the seed is used in candy making, abrasive cleaning products and explosives.
How to Plant a Black Walnut Tree
Consider planting black walnut trees if you live in USDA hardiness zones 5a through 9a with at least 25 inches of precipitation and 140 frost-free days per year. Black walnut trees do best growing in deep, fertile, moist yet well-drained soil with texture ranging from sandy loam, loam, and silt loam to silty clay loam.
Select a site that is facing north or east when planting black walnut and avoid areas in valleys, bottomland sites or where airflow is minimal, as all of these foster potential frost damage. You’ll need to choose an area of full sun as well.
To grow your own black walnut, it’s best to either purchase a tree, get a seedling from a local gardener who has a tree, or try to germinate your own by planting nuts. Gather the nuts and remove the husks. Plant six nuts, 4 inches apart in a cluster, 4-5 inches deep. As you no doubt have squirrels, pre-emptive caring for the black walnut trees is in order. Cover the planting area with cloth and pin it into the ground. Lay a layer of mulch (straw or leaves) over the cloth to prevent repeated freezing and thawing. Mark the planting site clearly.
The seeds will germinate in the spring. Remove the mulch and cloth in late winter. Once the trees have grown for a few months, choose the best ones and eliminate the others. Caring for black walnut trees is pretty straightforward after that. Keep them moist until they attain some size. Otherwise, the trees, although drought sensitive, have a deep taproot and should be fine as long as they are situated as stipulated above.