Effects of Seedling Type on the Establishment, Growth and Precocity of Eastern Black Walnuts (Juglans nigra L.) for Nut Production§

Abstract

Eastern black walnut (Juglans nigra L.) has potential for agroforestry practices in the eastern United States because of its value for nuts and timber; however, practices for optimum nut production are poorly defined. Studies were conducted to determine the type of planting material that can assure successful establishment of black walnut for nut production. The first study compared the survival and growth of bare root and container seedlings. Survival exceeded 95% with both stock types four years after planting. Bare root seedlings grew less during the first year after planting compared to container stock. No differences in annual growth increment were observed in the next three years. A study was conducted to compare flower production by commercially available open-pollinated seedlings derived from cultivars versus grafted cultivars at three locations in Arkansas and Tennessee. Seventy-two to 87% of the grafted cultivars flowered during the first four years compared to a maximum of 30% for the open-pollinated seedlings by the fourth year. A third study verified a previously reported relationship between trunk diameter and nut yields for grafted cultivars. These results suggest that landowners seeking to establish black walnut plantings for nut production should consider using container stock of grafted cultivars selected for improved nut quality.