The genus, Carya, contains several valuable timber and nut trees. Members of the Walnut Family, all of its major species are native to North America. All are tall stately trees with alternate compound leaves. Male and female flowers appear on the same tree, but indifferent clusters. The fruit is actually a fleshy drupe, though popularly called a nut. The nuts of several species are highly desired for eating. In the last 30 years several tree selections have been made, based on the flavor of the nut kernel or on the ease with which the shell can be cracked.
Growing pecans for their nuts has become an industry of considerable importance. Originally commercial Pecan-growing was largely restricted to Tex., Okla., Ark. and La. More recently named varieties are being grown throughout the South and as far north as southern Ind., Ill. and Iowa. The production of pecans in the United States has increased steadily during the last 40 years, presently totaling over 200 million pounds annually. This represents more than 10% of all nuts. The texture, aroma and appetizing flavor of pecans makes them valuable for flavoring baked goods, candies, dairy products, salads and desserts.
Several hundred varieties are now being grown. They vary in yield, bearing habit, resistance to insects and diseases as well as response to cultural practices and climatic conditions. Varieties commercially imported number about 15. Percent of kernel in the named varieties varies from 37 to slightly over 50.’Bradley’, ‘Stuart’, ‘Moneymaker’, ‘President’, ‘Pabst’, ‘Farley’, ‘Success’ and ‘Desirable’ are among the leaders in the Pecan orchards of Ga. and Fla. and in some of the states to the west.
Northern Pecan strains are growing in Mich., Ohio, Pa., parts of N.Y. and nearby states. Even in these states the cold does not harm the tree, but the nut crop usually fails to mature because of the shortness of the season. The northern limit of Pecan growing is Zone 4. Here the varieties ‘Busseron’, ‘Butterick’, ‘Green River’, ‘Indiana’, and ‘Niblack’ do well. In Tex. and the Mississippi Valley ‘Stuart’, ‘Schley’, ‘Van Demand’ and ‘Curtis’ are most commonly grown.
A young Pecan tree has a long, stout taproot. Successful planting is not easy because of the sparsity of lateral roots. Great care must be taken, when planting, to prevent injury of the taproot. A deep hole must be dug to accommodate it. Use rich sandy loam when planting the tree and remember that pecans become large, broad trees with a massive root system as they become older. They should be planted at least 75 ft. apart.
Once a young tree is established, it sends out long lateral roots in all directions. They are generally within 10 in. of the soil surface, so only shallow cultivation is practiced. Mulching with a variety of materials to conserve moisture and prevent weed growth is common.
Because of its commercial importance insect pests and diseases of Pecan require special attention. The hickory shuck worm is a destructive pest which destroys shucks and prevents normal nut development. Case-bearing caterpillars, weevils, scale insects, aphids, curculio and round-headed apple tree borer can all be troublesome. Their prevalence varies from state to state. Methods of control also vary. The extension service of the state university should be sought out for current control methods.
The Shellbark Hickory, C. laciniosa, becomes a tree, tall and broad, with light gray shaggy bark. The leaflets vary from 7 to 9. The nut is thick shelled, but the meat or kernel is delight-fully sweet. Of the several named Hickory selections, at least one is a Shellbark, originating in Pa. The nut is quadrangular, while the shell is thick, but reasonably easy to crack. The kernel is plump and of good flavor.
The Hican, a hybrid between C. illinoensis and C. laciniosa, has aroused considerable interest, because it can be gown successfully in the northern tier of states and will mature a crop of nuts. It is of special interest to members of the Northern Nut Growers Association. These varieties of the Hican, ‘Burlington’ and ‘Bixby’, produce the largest nuts. Bearing is often light. Nut quality is superior. Cultural practices are similar to those for Pecan.
The Shagbark Hickory, C. ovate, may reach 100 ft. in height. The leaflets are 5 in number (rarely 7), the margins fringed with hairs. The attractive gray bark loosens and comes off in wide plates during the growing season. Several named selections of trees with superior nuts are available in nurseries that specialize in nut trees. Among them are ‘Hales’ which originated in N.J., ‘Kirtland’, a rather large nut with a thinner shell permitting easy cracking and ‘Kentucky’ which has a kernel plump and angular, rich and sweet.
In times past the Mockernut, C. tomentosa, was gathered from the wild in those areas where trees were plentiful and productive. But the percent of kernel is so small the results were seldom worth the effort. The Pignut, C. glabra, is difficult to crack and has a minimum of meat. The Bitternut, C. cordiformis, is bitter, astringent and inedible.
Hickory trees are difficult to propagate vegetatively, although new techniques are simplifying the practice. All hickories have large tap roots when quite young, making trees difficult to handle in the nursery, limiting the number of nurseries that carry in stock.