Edward F. Gilman, Dennis G. Watson, Ryan W. Klein, Andrew K. Koeser, Deborah R. Hilbert, and Drew C. McLean
Introduction
A North American native, pignut hickory is usually seen at 50 to 65 feet in height with a 30- to 40-foot spread but is capable of slowly reaching 120 feet in the forest. The deciduous, 8- to 12-inch long leaves create a coarse, oval canopy, and the strong but irregularly spaced branches resist breakage in storms, making it useful as a shade tree. The green fruits are quite bitter and are popular with various forms of wildlife, but not man. Since fruits may damage cars as they fall and people could roll on the fruit and lose their balance, it may be best to locate the tree away from streets, parking lots, and other areas where cars regularly park. It makes a nice shade tree or median strip tree planted on 25- to 30-foot centers and turns a striking bright yellow in the fall.
Figure 1. Full Form—Carya glabra: Pignut hickory
General Information
Scientific name: Carya glabra
Pronunciation: KAIR-ee-uh GLAY-bruh
Common name(s): Pignut Hickory
Family: Juglandaceae
USDA hardiness zones: 5A through 9B (Figure 2)
Origin: native to the eastern half of the United States and extreme southern Ontario
UF/IFAS Invasive Assessment Status: native
Uses: shade; specimen
Figure 2. Range
Description
Height: 50 to 65 feet
Spread: 30 to 40 feet
Crown uniformity: symmetrical
Crown shape: oval
Crown density: dense
Growth rate: moderate
Texture: medium
Foliage
Leaf arrangement: alternate
Leaf type: odd-pinnately compound; made up of 5 to 7 leaflets
Leaf margin: serrate
Leaf shape: obovate, lanceolate
Leaf venation: pinnate
Leaf type and persistence: deciduous
Leaf blade length: 8 to 12 inches; leaflets are 3 to 6 inches
Leaf color: dark green on top, paler green and pubescent in the vein axils underneath
Fall color: yellow
Fall characteristic: showy
Figure 3. Leaf—Carya glabra: Pignut hickory
Flower
Flower color: male—yellow-green; female—green
Flower characteristics: not showy; male—2" to 3" long catkin; female—spike that emerges on clusters at branch tips
Flowering: spring
Figure 4. Flower—Carya glabra: Pignut hickory
Figure 5. Bract—Carya glabra: Pignut hickory
Fruit
Fruit shape: ellipsoid, obovoid
Fruit length: 1 to 2 ½ inches
Fruit covering: dry or hard nut that is enclosed in a 4-valved husk; splits half-way down the base with maturity
Fruit color: green to brown
Fruit characteristics: attracts squirrels/mammals; not showy; fruit/leaves a litter problem
Fruiting: matures in early fall
Figure 6. Fruit—Carya glabra: Pignut hickory
Trunk and Branches
Trunk/branches: branches don't droop; not showy; typically one trunk; no thorns
Bark: gray brown and smooth when young, developing scaly ridges that are interwoven in a diamond-like pattern with age
Hickory generally grows with one central leader, and branches are well spaced, forming a strong, wide angle with the trunk. The tree lends a coarse texture to the landscape, that contrasts nicely with the smaller-leaved trees, such as the evergreen oaks. This is an under-utilized native tree with potential for much wider use.
Pignut hickory grows best in sun or partial shade on well-drained, acid soils and is very drought-tolerant. Trees will show minor-element deficiencies on alkaline soils. It grows well in sand or clay, sending deep roots down below the trunk in well-drained soil. Hickory wood is versatile and is used for chair legs, tool handles (including axes and hammers), and for smoking meat and fish.
Propagation is by stratified seed or root-sprouts.
Pests
Borers, bagworms, and fall webworms, but none are normally serious. Fall webworms can devour large quantities of foliage during the summer and fall, but they cause no lasting damage and control is not needed. Galls are common on the leaves but cause no real damage.
Hickory bark beetle is a problem, particularly during droughts.
Diseases
Scab.
Reference
Koeser, A. K., Hasing, G., Friedman, M. H., and Irving, R. B. 2015. Trees: North & Central Florida. Gainesville: University of Florida Institute of Food and Agricultural Sciences.
