Carya aquatica, the bitter pecan or water hickory, is a large tree, that can grow over 30 metres (98 ft) tall of the Juglandaceae or walnut family.

In the American South it is a dominant plant species found on clay flats and backwater areas near streams and rivers.

Water hickory is a major component of wetland forests now in the south eastern US, because of the selective cutting of more desirable tree species for the lumber industry.

[2] Water hickory attains its best growth on moist but well-drained loamy or silty soils in the Mississippi River Valley and along some Coastal Plain streams.

It is common on clay flats, sloughs, and backwater areas, but seldom in coastal swamps or sites where soils are continually saturated.

[3] Important associated tree species are Quercus lyrata - Overcup oak, Quercus nuttallii - Nuttall oak, and Quercus phellos - Willow oaks; Ulmus crassifolia - Ceder elm and Ulmus americana - American elm; waterlocust and honeylocust (Gleditsia aquatica and G. triacanthos); pecan; green ash (Fraxinus pennsylvanica); sugarberry (Celtis laevigata); persimmon (Diospyros virginiana); red maple (Acer rubrum); and baldcypress (Taxodium distichum).

), swamp-privet (Forestiera acummata), roughleaf dogwood (Cornus drummondii), buttonbush (Cephalanthus occidentalis), possumhaw (Ilex decidua), and water-elm (Planera aquatica).

Many of our present stands of water hickory, especially on imperfectly drained flats, have been regenerated and released by heavy preferential logging of more valuable species.

On poorly drained sites, where competition is not so intense, water hickory grows to fill openings created by windthrow and natural mortality as well as logging.

Seedling development- After seedfall in the autumn, the seeds lie dormant until germination in late April through early June.

Because of their extended dormant season, water hickory seedlings are able to survive late-spring floods better than most of their would-be competitors.

Slow growth rates are typical of water hickory in competition with oaks, sugarberry, gum, and other species on good sites.

Maximum mean annual production of a pure stand (found rarely) on a good site has been established at 10.5 m³/ha (150 ft³/acre).

The wet clayey soils where water hickory usually is found restricts the entire root system to fairly shallow depths.

The taproot eventually becomes the source of a coarse, wide spreading but shallow lateral root system.

The taproot of a 30-cm (12-in) individual, excavated on moderately well-drained clayey soil, ended abruptly with three large lateral roots growing out at right angles.

Owing to its slow growth, poor quality, and consequent low value, most silvicultural operations are intended to favor species other than water hickory.

No races have been recorded; population and geographic variations have not been studied except for the hybrid Carya x lecontei Little (C. aquatica x illinoensis).