This native species is the most dependable nut plant for Illinois. Several varieties, which have superior nuts, more disease resistance, and more dependable production than other varieties of black walnuts, are listed in the suggested variety list. Walnuts prefer deep, fertile, moist soils such as are found in river bottoms, but they will grow in a wide range of soils. Avoid excessively wet soils. The spicy flavor and aroma of black walnuts make them especially adapted for use in cooking and baking.
All of the hickory species are tall, handsome trees. Shagbark and shellbark species and shagbark-shellbark hybrids are preferred for nut production. Several varieties with improved nut quality have been developed. Bitternut, pignut, and mockernut hickories produce nuts of inferior quality, but the fall coloring of their leaves is more spectacular than that of the species with better nut quality. These species of hickories are all native to Illinois. Shagbarks are best adapted to upland soils; shellbarks grow best in alluvial or floodplain soils.
Pecans are related to the hickories and, like the hickories, develop into large, attractively shaped trees.
So-called hardy northern pecans are native to the bottom lands in southern Illinois along the Wabash, Ohio, and Mississippi Rivers. The southern or paper-shell types require a longer frost-free growing season for good nut filling than is usual in even the most southerly part of Illinois. Proper filling of hardy northern pecans also requires a certain period of frost free weather, the amount of which determines the northern limits of nut production. These trees bear more regularly in area 1 (see map below). They are less dependable in area 2, and occasional production can be obtained in the southern part of area 3.
Pecan hardiness zones in Illinois
Pecans produce best in fertile river bottom soils, but some production can be obtained from trees planted on fertile upland soils.
Chinese chestnut trees are attractive, medium-size trees with a spreading, rounded form. They do well in most locations in Illinois but may fail on heavy, poorly drained soils. Most important, they have a fairly high resistance to chestnut blight disease--a disease that has almost eliminated the American chestnut from its native habitat.
Chinese chestnut trees are available from nurseries as young trees produced from seed (seedling trees) and as grafted named varieties. The seedling trees may vary somewhat in tree and nut characteristics and may not be as productive as grafted trees, but grafted trees may suffer from graft-incompatibility problems and be short-lived.
Chinese chestnuts are self-unfruitful. There is enough variation in seedling trees, however, to provide cross-pollination if 2 or more trees are planted. For cross-pollination of grafted trees, at least 2 different varieties should be planted.
American chestnuts were largely destroyed in the early 1900s and should be grown in areas where chestnuts were not native to avoid Chestnut blight. The nuts are very sweet and easy the take out of the shell. The Connecticut Experiment Station has released American Chinese hybrids that are disease resistance. A number of nurseries and orchards have recently started to offer American Chestnut seedlings from disease-free stock.
These are hybrids resulting from a hickory-pecan cross. As would be expected, the characteristics of the tree and nut are a blend of the characteristics of the parents. They are an interesting novelty but most are not heavy bearers.
The major varieties of Persian walnuts grown in California require too many heat units or too long a frost-free growing season for production in Illinois. Some shorter-season varieties can be grown in Illinois, but blossom kill from late spring frosts is a constant threat to production in all areas of the state.
Walnut blight, a bacterial disease, is serious on susceptible varieties. Use grafted trees of the more resistant varieties (see suggested variety list). Persian walnuts are medium-size trees.
Filberts are not trees but multistemmed large shrubs; they are desirable in the home landscape for their shape and fall color. Losses to wildlife (birds, tree squirrels, ground squirrels) present the main problem in nut production, for it is almost impossible to protect the nuts of these shrubs from premature harvest by wildlife.
Filazels are hybrids of European Hazelnut and beaked hazels. They are earlier ripening and thinner shelled than European hazelnuts. Extremely hardy seedlings from the Peace River Valley are commercially available.
Trazel is a hybrid of Turkish Tree Hazel and European Hazel. It is drought- and wind-tolerant and winter-hardy tree. Nuts are larger, heavy ripening, and produced 10 to12 to a cluster.
The so-called hardy almonds are generally unproductive in Illinois. Because they bloom early in the spring, the blossoms are usually killed by frost. When they do bear, the nuts have very poor edible qualities and are difficult to shell.
These trees are very susceptible to walnut bunch disease. This disease is so severely damaging in Illinois that they are not very productive.