Borne in terminal clusters of 2-10 individuals. The shuck dehisces along regular sutures into 4 valves, unlike walnuts which lack these sutures. Nuts are ovoid, 1-2 inches long, containing a large embryo composed mostly of two cotyledons or kernals. Cotyledons are separated by a thin, papery central plate extending from the inner layer of the endocarp. Fruiting occurs 4-6 years after transplanting, although maximal yields may not be achieved for 10 or more years.
Pecans are native to floodplains and river-bottoms, and have an inherently high water requirement.
Irrigation has been shown to increase yields even in the humid southeastern US, and is essential for western orchards. Leaf analysis can be used as a guideline for when to apply zinc, either to the foliage or to the soil surface. Disease pressure is worse in humid climates, as for most horticultural crops. Most pecan cultivars require growing seasons of 180-220 days. Pecans are among the last tree crops to resume growth in spring, apparently due to a high post-rest heat requirement.