Bitternut Hickory (Carya cordiformis)

A deciduous tree from the Walnut Family (Juglandaceae)

Bitternut Hickory, found throughout all of Ohio, is a common Hickory that has bitter nuts usually too ill-fit for human consumption, as its name implies. It is unlike Shagbark and Shellbark Hickories in more ways than this, in that its leaflets are more lance-shaped, its fruits have four-winged husks and are thin-shelled, its bark is sinewy when young and with criss-crossing ridges at maturity, its small winter buds are yellow and valvate, and its twigs are slender and rapidly growing.

Bitternut Hickory grows to 60 feet tall by 25 feet wide when found in the open, with a crown of ascending branches and a lower canopy of pendulous branches. As a member of the Walnut Family, it is related to other Hickories and the Walnuts.

Planting Requirements - Bitternut Hickory prefers deep, moist soils that range from poorly drained to well-drained, but is often found in drier conditions. Its alternative common name of Swamp Hickory implies that it can be a companion to Shellbark Hickory, which strongly prefers bottomland sites. It tolerates shade in its youth, but needs full sun at maturity, and is adaptable to acidic, neutral, or alkaline pH soils. It is found in zones 4 to 9.

Potential Problems - Bitternut Hickory has cleaner foliage in late summer as compared to other hickories; that is, its leaflets tend not to be as riddled by chewing insects. It has virtually no disease or pest problems, and is rapidly growing. As with all Hickories, it is constantly raining debris from its fruit crop from late summer throughout autumn, making fall cleanup in urban areas more challenging.

Leaf Identification Features

>Leaves of Bitternut Hickory are alternate and pinnately compound, up to one foot long, and usually display seven narrow leaflets (ranging from five to eleven), with fine serrations on their margins.

Spring and summer leaf color is medium green to dark green, while fall color is often green to chartruese, but sometimes a brilliant golden-yellow in excellent seasons.

Other Identification Features

Male and female flowers of Bitternut Hickory occur on the same tree and thus this and other hickories are termed monoecious. Three-branched staminate (male) catkins droop from the previous year's twig growth, while pistillate (female) flowering spikes occur at the terminus of the current season's growth. Flowering occurs in mid-spring.

The fruits of Bitternut Hickory are composed of a bitter innermost kernel, surrounded by a hard bony shell with four ribs, surrounded by a thin outer husk that splits into four quarters when ripe. The fruits are distinct in that they have four easily visible ribs on the outer portion of the husk.

The single most distinctive feature of Bitternut Hickory from mid summer until early spring is its sulfur-yellow buds. They are termed valvate, because they are composed of pairs of scales (like the bills of a duck), rather than multiple scales overlapping around the bud. The terminal is the longest and most flattened, and appears to be two miniature leaves.

The light gray bark of Bitternut Hickory is the smoothest of the Hickories, and has a sinewy, muscled, sometimes twisted character. With age, it develops interlacing ridges and shallow furrows that may cause it to be mistakenly identified as an ash (which also has compound leaves, but they are opposite, rather than alternate). Bitternut Hickory never develops the peeling character of Shagbark or Shellbark Hickories.