Nut Crops Trees for Food, Ornament, Shade, and Wood

by Richard A. Jaynes and Howard L. Malstrom.

Richard A. Jaynes is Geneticist, Connecticut Agricultural Experiment Station, New Haven. Howard L. Malstrom is Associate Professor, Texas A&M University Research Center, El Paso.

Trees are planted to give shade, to improve landscapes, and sometimes to produce food for man or wildlife. Nut trees provide all of these benefits. Wherever trees can be grown in the United States there are one or more kinds of nut trees suited for the climate.

Black walnut, pecan, and hickory can reach heights beyond 90 feet when mature. Other nut trees are low and spreading, like Chinese chestnut, butternut, Japanese walnut and heart-nut. In outline they may resemble old fashioned apple trees. Almond trees are even smaller, while filberts and chinkapin chestnuts are little more than shrubs. If an evergreen is needed, large seeded nut pines are suitable.

The pecan is the most popular nut tree native to the United States. It is a species of hickory and in the same plant family as walnuts. The pecan grows throughout the southern United States from the Carolinas to Arizona and north, along river bottom land, as far as Iowa in the Midwest.

Pecan trees prefer a rich, deep, well-drained soil, and long, warm growing seasons. In the South the frost-free period extends from 190 to 220 days, but it may be as short as 150 days in the Midwest. Although trees will survive in much of the Northwest and Northeast, the cooler summers don't allow development of full kernels.

Numerous varieties have been selected for their fine nuts and other desirable characteristics. Early maturing selections are required for the Midwest. In the high rainfall area of the Southeast, disease-resistant varieties that need less spraying are preferable.

Besides pecan trees there are several other native hickories. Two, shellbark and shagbark, are notable for their sweet tasting nuts. They are hardier than pecans. Though shell-bark and shagbark are not grown in commercial orchards, amateur nut growers propagate and grow several selections having large kernels that separate readily from the shell when cracked. Shellbark hickory does best on lowland and river bottom soil. Shagbark is common on thinner, more acid, upland soils.

Eastern black walnut is our most valuable native hardwood, and the nuts are harvested in huge quantities each year. The nuts' tangy flavor isn't lost even in baking.

Black walnuts, native to the eastern United States, are grown from Nebraska and Texas to southern Vermont and South Carolina. They do best on limestone-derived soils.

Persian (English) walnut is an introduced species. Like almond, filbert, and pistachio, it is adapted to the West Coast. These nut trees all originated in arid, mild climates of Europe, Asia, and the Middle East. The climate of parts of California, Oregon, and Washington is similar to that of their native habitat. Hardy members of the species are grown extensively in home and farm yards in the Midwest and East. They are often referred to as the "Carpathian" strain because many originated in the colder Carpathian mountains of Europe.

Butternut is an extremely hardy, native walnut valued for its nuts in the colder areas of our north central and northeastern states. Other species of walnut, such as the Japanese walnut and heartnut and their hybrids, are locally important.

Commercial production of filbert (hazelnut) is limited largely to Oregon's Willamette Valley where the European filbert variety Barcelona is the principal selection grown. The American filbert, hybrids with the European filbert, as well as some European varieties are grown in the eastern United States. Eastern filbert blight and cold winters restrict their wider use.

Almonds and pistachio are grown in the Sacramento and San Joaquin Valleys of California and to a limited degree in other southwestern States. Spring frosts, high humidity, and rainfall limit their success elsewhere.

American chestnut was destroyed by an introduced bark parasite in the early half of this century. Blight-resistant Oriental chestnut trees, notably the Chinese chestnut, are widely grown for their nuts. They are hardy and thrive wherever peach trees can be grown.

Chinkapin chestnuts, native to the Southeast, are small trees or shrubs that bear small, tasty nuts. The Chinkapin nut size makes them especially suitable producers of wildlife food.

Pecan Varieties

* I. Pollen shed before females are receptive. H. Pollen shed after females are receptive Interplant at least one tree from each group for best pollination.

Developing burs on a Chinese chestnut tree.

Macadamia is a tropical nut tree of Australia and now an important crop in Hawaii. The tree has met with some success in warmer areas of California and in Florida.

Other trees such as oak, beech, ginkgo and pine, often not thought of as nut trees, can be grown for their nut fruit. Among the nut pines, pinyon pine is native to the and Southwest, Korean pine is hardy in the Northeast, and Italian stone pine is hardy in the Deep South.