Growing black walnut
nut
Pollination
As with English walnut, a second tree improves nut set.
Growing it
Zones 4-9. Native, massive, and the strongest juglone producer - keep it well away from a vegetable garden. Prized, hard-shelled, richly flavoured nuts.
Where black walnut grows best
Hardy in zones 4-9, and it needs enough winter cold - about 700-1500 chill hours - to flower and fruit well. Combining the two:
Good fit across most of: Arkansas, Colorado, Connecticut, Delaware, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, New Hampshire, New Jersey, North Carolina, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Dakota, Tennessee, Utah, Vermont, Virginia, West Virginia, Wisconsin, Wyoming. Also parts of Alabama, Alaska, Arizona, California, District of Columbia, Georgia, Mississippi, Nevada, New Mexico, New York, North Dakota, Oregon, South Carolina, Texas, Washington.
Will you get enough chill?
Black Walnut needs roughly 700–1500 hours between 32 and 45 °F over winter to break dormancy evenly. Check your area with the chill hours calculator. Low-chill breeding has pushed many varieties well below the figure here, so read the plant tag.
Questions gardeners ask
What zone does black walnut grow in?
Black Walnut grows in USDA hardiness zones 4-9. In the warmest of those (zone 8, 9), winters may be too mild to give the chill it needs, so choose low-chill varieties there.
How many chill hours does black walnut need?
Roughly 700-1500 hours between 32 and 45°F over winter, depending on the variety. Low-chill varieties need less - check the plant tag, and estimate your own area with the chill hours calculator.
Does black walnut need a pollinator?
Partly self-fertile — crops much better with a partner. As with English walnut, a second tree improves nut set.
Which states can grow black walnut?
Black Walnut suits most of Arkansas, Colorado, Connecticut, Delaware, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Maine, Maryland and 21 more, and parts of 15 other states where the right zones occur. Your own zone and chill hours matter more than the state.
Chill and pollination are given at the fruit-type level; specific cultivars can differ. Values are typical ranges for home-garden planning.