Bitternut Hickory - North American Trees

This is an excerpt from the Book called “NATIVE TREES FOR NORTH AMERICAN LANDSCAPES “ . Continue reading to learn more about Bitternut Hickory – North American Trees, thanks to the author.

Carya Cordiformis

BITTERNUT HICKORY

DESCRIPTION: Bitternut hickory, or simply bitternut, is one of the so-called pecan hickories (section Apocarya), which are distinguished by winter buds that are not covered with overlapping scales. The buds of bitternut are unique in that they are a bright sulfur-yellow, giving the tree its alternate name, yellowbud hickory. This species is, by a narrow margin, the northernmost and most widespread hickory, as well as one of the fastest growing.

Bitternut is also among the largest hickories, frequently exceeding 100 feet (30 m) in height on the rich sites where it prefers to grow. The largest known specimen, at Great Smoky Mountains national Park, is nearly 150 feet (45 m) tall and 4 feet (1.3 m) in diameter. Bitternut typically develops several primary ascending limbs, forming an arching shape. Its bark is tight and relatively smooth, occasionally developing scattered horizontal fissures that resemble the scars inflicted on fence-row trees by old wire.

LEAVES: Bitternut leaves are narrower than those of most other common hickories and are pinnately compound with seven to nine leaflets. They attain a lighter autumn hue than the leaves of other hickories, turning a bright, clear yellow. Bitternut hickories are among the first of our major forest tress to display fall color, and their tall, yellow crowns can be seen from a long distance.

Flowers And Fruit: The flowers appear as the leaves are reaching full size. The pendent male catkins hang like tinsel from the branches and are visible below the leaves, looking like miniature festoons of moss.

The nuts develop from the smaller, pistillate flower spikes. Unlike most hickory nuts, bitternut hickory nuts seem useful for little else than potent ammunition for young kid’s slingshots. Most nuts are too bitter to be of much interest even to squirrels, although they probably serve wildlife as emergency rations when other foods are scarce. Since they have thin husks and shells, any palatable nuts are easy to eat.

BEST SEASONS: FALL (they clear yellow of bitternut combines well with the somber greens and earliest reds of the surrounding hardwood forest). LATE SPRING (the staminate catkins embellish this species, already among the most finely textured hickories). SUMMER AND WINTER (a fine tree for lawn or forest in all seasons).

NATIVE AND ADAPTIVE RANGE: Hickories are almost exclusively North American natives, and bitternut is the most common and widespread hickory through most of our region. It grows naturally on mesic sites and bottomlands from central Minnesota and Trois-Rivieres, Quebec, down to northern Florida and eastern Texas. It can do well in protected valleys up through USDA zone 3.

CULTURE: Saying that bitternut is one of the easiest hickories to transplant is analogous to claiming that breaking one arm hurts less than breaking both. All hickories are difficult to move and are best established as small seedlings or containerized plants, or by planting seed in the permanent locations desired for the trees. Soak the fresh seeds in water for a couple of days, then plant them in fall and protect the spot from squirrels and mice. Alternatively seeds can be planted in containers if air-pruning pots, root-restricting fabrics, or copper applications are used to produce a branching root system. These container-grown seedlings can then be planted in a nursery bed for a few years and will move relatively easily (for hickories) when it’s time to find them a permanent home.

Hickories can be shocked by root disturbance later in life and should not be subjected to construction or soil compaction within their root areas. Bitternut will grow very well with adequate water and fertility, responding better to such care than some of the growing conditions.

PROBLEMS: Hickories may be stronger, pound for pound, than steel; but the pecan types, including bitternut, are less so than the others. The frame of this species is further weakened by its branching structure, which is frequently divided into several ascending primarily limbs. Nonetheless, it remains one of our stronger shade trees in the face of wind or ice storms.

In closely maintained turf areas, the small nuts of bitternut hickory can be a liter problem, usually with no offsetting gastronomic values. Sapsuckers (our only noxious woodpeckers) seem to prefer the sap of bitternut over that if other species and occasionally damage the bark. All hickories are preferred hosts for masses of fall webworms (Hyphantria cunea), which are generally more ugly than harmful, due to their late season activity. In spite of their hard, dense wood, stressed or damaged hickories are attacked and sometimes killed by the painted hickory borer (Megacyllene caryae), the hickory bark beetle (Scolytus quadrispinosus), and other borers.

CULTIVARS: There are no named cultivars of bitternut hickory, but its large natural range should yield regionally adapted ornamental selections.

SIMILAR AND RELATED SPECIES: Among the other pecan hickories are the water hickory (Carya aquatica) and nutmeg hickory (C. myristicaeformis), both of which develop shaggier bark than bitternut.

Water hickory is remarkable for its tolerance of seasonally wet soils. It is a swamp-forest tree that not only can withstand protracted flooding during the growing season but can also grow equally well when planted on well-drained sites. A tree of the Mississippi Valley and the Coastal Plain, it grows just as well on dry land at my arboretum in central Illinois. Water hickory and bitternut both hybridize in the wild with pecan, producing trees called bitter pecans.

Nutmeg hickory is an uncommon species with leaves that are attractively whitened underneath. It grows in the United States in scattered relictual stands on upper terraces of river floodplains, along the Red River in Texas, and in a few other isolated locations across the Southeast. Like its relatives, it also grows well in cultivation in central Illinois in my USDA zone 5 climate. Saplings of this species are more tolerant of shade than other hickories. The U.S. national champion nutmeg hickory is almost as tall as the record bitternut, though not as thick. It becomes even larger in the southern part of its range, in Nuevo Leon, Mexico. The record water hickory is only about 100 feet (30 m) tall but has an immense buttressed trunk more than 6 feet (1.8 m) in diameter.

COMMENTS: Bitternut and its relatives are among our best forest soil builders due to the mineral content of their leaves. It casts a relatively light, open shade compared with other hickories, allowing turf or ornamental plants to thrive under its canopy.

Bitternut has a reputation, as its name implies, for having bitter nuts. On one occasion I tried to play a joke on my young nephew by picking up some of these nuts, cracking them open with a rock, and pretending to eat them. Monkey see, monkey do, and he followed suit. When he ate a second, and then a third, I became suspicious. As it turned out we had stumbled upon the only sweet-tasting bitternut hickory tree I have ever found. My mischievous little joke had helped us find a great nut tree that we would not have tasted otherwise.

This tree and other hickories also serve as primary hosts for some magnificent and relatively harmless moths, including the beautiful, nocturnal luna moth, several colorful underwing moths, and the scary-sounding little funeral dagger wing. But the most impressive tenant of the hickories is the giant regal moth, with its 6-inch (15-cm) wingspan and its unforgettable larva, the hickory horned devil, our largest North American caterpillar.