New York Natural Heritage Program
Big Shellbark Hickory
Carya laciniosa (Michx. f.) G. Don

General Description [-]
Big shellbark hickory can grow to be a large tree more than 100 feet tall. The trunk is usually straight and free of branches in the lower half. The crown is oblong to rounded. The bark is light to dark gray and peels off in long shaggy strips like shagbark hickory. The twigs are stout, orange-brown, and have large, dark brown, hairy, winter buds that turn yellow in the spring. The leaves are alternate and compound with seven leaflets but sometimes have as few as five or up to nine leaflets. The three leaflets at the end are larger than the ones below. The edges of the leaves are toothed and without hairs at the tip of the teeth. The male flowers are on long, stalked, dangling catkins in clusters of three. There are 2-5 female flowers on short stalks at the ends of the new branches. These flowers produce the large, rounded, brownish yellow fruits up to 2 1/4 inches in diameter which are usually flattened at the top. The husk easily splits open to reveal a hard, round, flattened nut that is pointed at both ends and up to 2 inches long. The shell is very hard and thick and the kernel is sweet.

Best Life Stage for Proper Identification [-]
The key to identifying this species is by collecting the nuts. There should be old nuts on the ground throughout the year. A habitat description will also be very helpful.

Similar Species [-]
Most hickory trees have nuts that range in size from 1-3 cm, compared to the 3-6 cm size found on big shellbark hickory. Many of the other New York hickories are more of an upland tree. You might encounter Carya ovata and Carya cordiformis on a floodplain but only Carya ovata has shaggy bark. Carya cordiformis has thin flat bark with fissures and a distinctive sulfur bud. Its nuts are thin shelled and bitter. Carya ovata has 5-7 leaflets that are glabrous underneath or only with a few scattered hairs. The margins have numerous hairs however. Its nuts are thin shelled and sweet. Carya tomentosa also has large buds and 7-9 leaflets, but it is typically restricted to upland sites, has a more rounded fruit, and the nuts are smaller (1.5-3 cm). It also lacks shaggy bark.
Big Shellbark Hickory Images
click to enlarge
The Best Time to See
This tree is obviously visible year-round, but the leaves begin to emerge mid-May and persist until mid-fall. The flowers appear mid-May to early June and fruits develop shortly afterward. Mature fruit are probably not present until early August, but these persist on the trees until a few hard frosts. Fruit from previous years will likely be scattered on the ground and located just below the leaf litter. Surveys may be conducted at any point during the growing season.
Vegetative Flowering Fruiting
The time of year you would expect to find Big Shellbark Hickory vegetative (blue shading), flowering (green shading) and fruiting (orange shading) in New York.