Shellbark Hickory (Kingnut)

Size, growth and what to expect

The first shellbark hickory nuts come at about 40 years and the biggest crops between 75 and 200, with a good crop about every second year. Growth is slow to match. Ohio Valley seedlings measured 4 inches after one year and 22 inches after five. Our growth estimator models it at about a foot a year on an average site. It reaches 60 to 80 feet with a crown 40 to 60 feet wide. Trees live about 300 years, and some reach 350. A trunk section in a museum collection shows 340 annual rings. Only a tiny share of trees is ever dated this way, so older ones may exist.

The nuts are the largest of any hickory, egg-shaped and 1 to 3 inches long, in a husk up to a half inch thick that splits in four. Ducks, turkeys, squirrels and foxes eat them. Kingnut, its other name, refers to that nut.

It grows wild from western New York and southern Michigan to Iowa, south to Kansas and Oklahoma, and east through Tennessee into Pennsylvania. It favors river terraces that flood for a few weeks in spring.

How to grow Shellbark Hickory

Shellbark hickory wants full sun or part shade on deep, moist, fertile loam; it takes a few weeks of shallow flooding in spring and does poorly on heavy clay or a dry ridge. It grows broad as well as tall, so give it 30 feet from the house and off the drive, where the nuts drop. Set trees 40 to 60 feet apart.

Saplings ship bare-root or potted. Plant a dormant sapling from leaf fall until bud swell, in a hole deep enough for the taproot to hang straight and wider than the rest. Set the flare at grade, put the native soil back in, and keep mulch off the trunk. Sow nuts in fall an inch deep under hardware cloth, or squirrels dig them up. For spring, soak them a few days, then hold them damp in the refrigerator for 90 to 120 days. They come up in late spring. Seedlings like light shade the first summer and put their first year into the taproot.

Water weekly through the first summer if rain is short. Deer browse the leaves and rabbits gnaw hickory bark, so tube the stem for three years and keep mulch thin at the base against voles. Prune in the dormant season only to keep one leader; hard cutting brings water sprouts, and twig girdlers may clip the tops of young trees.

Growth is slow; seedling trees bear at about 40 years and then a good crop about every second year, two or three bushels from a thriving tree. Male and female flowers share a tree, opening after the leaves in April and May; a second shellbark nearby gives a bigger crop of better nuts. Late frost nips new growth. Weevils and shuckworm take some of the crop and drought invites the hickory bark beetle; no disease threatens it.