The Future is Abundant
A Guide to Sustainable Agriculture

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Northwest Nut Crops

Nuts can be an important element in a balanced diet. They are rich in protein, oils and carbohydrates, and can serve as a substitute for animal protein. There are nut trees adapted to almost every part of the Pacific Northwest, including walnuts, filberts, hazelnuts, chestnuts, beechnuts, pine-nuts, almonds, pecans, sweet-pit apricots, and gingko nuts.

Nut trees are long-term investments, and success depends on selecting the best species and cultivars for each location. Unfortunately, with the exception of walnut and filbert, there has been little research on nut culture in the Northwest, so choosing nut varieties is somewhat more difficult than choosing fruit varieties, for example. If you are thinking of growing nuts, it would be wise to consult experienced neighbors, regional nut tree nurseries, and your county Extension office.

Nut Culture

Nut trees lend themselves to a multi-level, diversified agriculture. The taller-growing nut trees can form the upper story, while others, such as filberts, can be grown as middle story elements. Walnuts, butternuts, chestnuts and hickories do not leaf out until late in the spring, and thus can be used in situations where winter and early spring sun, combined with summer shade, is desired. Numerous shrubs and herbs are adapted to the partial shade of nut trees.

Some types of nut trees come fairly true to seed, while others show a great degree of variance. For this reason, many of the trees sold through nurseries have been grafted to select nut cultivars. Some nurseries, however, also sell lower-priced, non-grafted nut seedlings. Commercial orchardists and backyard growers with limited space will want to plant grafted trees.

Most nut trees develop deep, strong taproots in their first year of growth. This makes them difficult to transplant successfully, especially if grown for two years in the nursery and before transplanting. To avoid transplant shock, nuts may be planted in the spot you wish them to grow. If fall-planted, a deposit of fresh cow manure will discourage rodent pilferage plus act as a fertilizer and mulch. Mark each seed witha stake so it can be located easily. After one or two years of growth the seedling may be grafted. Allowing seedlings to grow ungrafted increases the genetic base of the species and allows new cultivars to come into existence.

Rodents frequently cause heavy damage to young nut trees and some method of winter screening is advisable. Trees can be mulched with stones to good advantage since water is conserved and competing vegetation and mice are discouraged. Water requirements of different nut trees vary. Most prefer moist, rich soil, but some oaks, pines, almonds and sweet-pit apricots are drought tolerant.

Filberts and Hazelnuts

There are fifteen Corylus species in the north temperate regions, two of which are native to North America, C. americana and C. cornuta. Both species are referred to as wild hazelnuts. C. americana is native in the eastern forests while C. cornuta is found across much of Canada and througout the Maritime Northwest. Its habitat includes clearings and forest understories. The nuts are tasty but small, and a human gatherer has to be quick to compete with the wide variety of wildlife which feed on them.

The cultivated filberts are the rsult of hybridizing between the native European species, primarily C. maxima and C. avellana. Most Corylus species are multi-stemmed shrubs. The Turkish hazel or columnar hazel (C. colurna) and the Chinese hazel (C. chinensis), however, form columnar trees up to 100 feet tall. They are being crossed with domesticated filberts to create a hardier, tree form of filbert.

The long, moderate growing season of the Maritime is ideal for filbert production. In fact, the Willamette and the lower Columbia valleys produce 98% of the U.S. filbert crop. Filberts also grow well in the Interior wherever the climate is suitable for sweet cherries. Filberts grown in the hotter parts of the Columbia Basin will benefit from an overstory of larger trees for shade and wind protection.

The Barcelona has been the leading filbert cultivar for many years, but the recently introduced Ennis cultivar (developed by researchers at Oregon State University in Corvallis) will most likely outrank it in the next decade, as Ennis gives significantly higher yields and a higher percentage of filled shells. Butler and Hall's Giant are good pollinators for Ennis.

The Eastern filbert blight, a fungus disease, was introduced into southwest Washington 10-15 years ago and is just beginning to spread into Oregon. The blight is especially injurious to young trees and causes tip die-back on older trees. It is partially controlled by proper pruning and spraying with fungicides.

Hickories and Pecans

There are 22 Carya species, most of them native to eastern North America. Its most famous member, the pecan, is a southern tree with little possibility of adaptation to the Northwest outside of the most favored locations in the lower Columbia Basin. The shagbark and shellbark hickories are hardier, but still require a long, hot growing season for their nuts to ripen. Superior cultivars which have thin shells and large nutmeats are available and deserve further trial in the warmer zones of the Interior Northwest. Hickories need a deep, rich soil for best development.

Chinquapins

The chinquapins are closely related to the chestnuts. There are only three species, the largest of which is the golden chinquapin (Castanopsis chrysophylla), which is native to the Pacific Northwest. The golden chinquapin grows up to 20 feet in height in the Klamath mountains, but gradually reduces in size as it nears the top of its range, becoming a small shrub in the Puget Sound area. Its nuts are small and sweet, and it is a fine ornamental.

Almonds

Almond trees require long, hot summers to ripen their nuts, and are best suited to areas where peaches can be grown successfully. A favorable location with a deep, light soil is a necessity. Recent introductions of dwarf trees (such as Zaiger dwarf almonds offered by the Dave Wilson Nursery) can be grown as container plants.

Sweet-Pit Apricots

Sweet-pit apricots are relatively unknown in North America, but have the potential of becoming an important crop in regions too cold for almonds but suitable for apricots. The most famous sweet-pit apricots are the Hunza-cots. The people of the remote, mountain country of Hunza have made sweet-pit apricot kernels a main part of their diet for centuries. Most apricot kernels contain a form of cyanide poison which accounts for their bitterness. Sweet-pit apricots, which taste like almonds, do not contain this substance and are safe to eat.

Sweet-pit apricots are multiple-use trees yielding fruit, nuts, carving wood, and a source of spring bee food. Two sources at present are Bear Creek Nursery and Grimo Nut Nursery.

Chestnuts

Along witha rich supply of carbohydrates, chestnuts contain about 5% oil and 5% protein, making them the "potato" of the nut family. Because of their relatively low oil content, chestnuts can be used as a diet staple, dried and ground into flour.

The American chestnut (Castanea dentata) was once the dominant tree of eastern North America. Unfortunately, the chestnut blight (Endothia parasitica, introduced in 1904) has virtually eliminated the chestnut tree from its original range, and is now attacking the European chestnut (C. sativa) in western Europe. However, the Chinese chestnut (C. mollisima) and the Japanese chestnut (C. crenata) are fairly blight-resistant. Some progress has been made in developing blight resistant American chestnuts, and breeding between species is underway with the hope that this forest giant can be restored to its former range.

All four of the chestnut species mentioned above are being grown in the Pacific Northwest. The best yields of sweet, well-filled nuts are obtained in areas where peaches do well. The trees will grow in cooler areas but are less productive. Breeding and selection are underway to produce satisfactory cultivars for a wider variety of climates. Chestnuts grow best in full sun on deep, well-drained, loamy soil. They begin bearing within several years of planting and rarely self-pollinate, so two or more trees should be planted close together.

A diminutive relative of the chestnut is the Allegheny chinquapin (C. pumila). This small tree or shrub produces a sweet nut which was used by the Indians to produce a chocolate-like confection. It is adapted to a variety of habitats, including dry, rocky hillsides and streambanks.

Of particular interest are hybrids between the American and Chinese chestnut. These trees are blight-resistant, have larger nuts than the American, stronger growth than the Chinese, and produce valuable straight trunks in addition to the nuts. Several valuable varieties have been reported from China, including C. sequinii, a dwarf Chinese chestnut of three to eight feet, and C. vilmoriniana, a large, American type with superior taste.

Pine-Nuts

Pine-nuts are quite tasty and nutritious. They have been a staple food for many people around the world. Some species which produce seeds large enough to be worthwhile harvesting include the Italian stone-pine (Pinus pinea), pinyon pine (P. cembroidies), Korean stone pine (P. koreansis), Swiss stone pine (P. cembra), Siberian stone pine (P. siberica), sugar pine (P. lambertiana), digger pine (P. sabiniana), limber pine (P. flexilis), and whitebark pine (P. albicaulis). Subar pine and whitebark pine are native to the Northwest. Pinyon pine and digger pine stop just south of its boundaries. Swiss stone pine and Siberian stone pine are extremely hardy and slow growing, and are used as urban ornamentals. The Korean stone pine offers the most promise in the Northwest because of its hardiness, fast growth, and large nuts.

Walnuts

There are fifiteen species of walnuts, the most famous of which is the Persian or English walnut (Juglans regia). Since earliest recorded history, people have been selecting and planting the best of these trees, producing thousands of named cultivars in the process. Walnut breeders are now going back to wild genetic stock from Europe and Asia to breed in hardiness, disease resistance and other desirable characteristics. The Carpathian walnut (a hardy strain of J. regia) was discovered by a plant explorer in the Carpathian mountain region between Greece and Yugoslavia.

The Manchurian walnut (J. manchurica) produces a small, hard-shelled nut which has little value for commercial nut production but which is proving valuable for rootstocks and for breeding work with Persian walnuts.

The Japanese walnut (J. sieboldiana) has been bred over centuries to produce a rich, sweet nut called the Japanese heartnut. Though it has one of the thickest shells of the walnuts, it is easy to crack. The heartnut is one of the most ornamental walnut trees, with lush foliage reminiscent of tropical plants and large, pendulous strings of nuts. The heartnut is similar in hardiness to the Persian walnut.

Superior cultivars of the black walnut (J. nigra) and butternut (J. cinera) are available which are thin-shelled and have large nutmeats. Through the efforts of Carl Weschke and other nut breeders, cultivars of exceptional hardiness have been developed.

The high value of walnut wood is well known. The quality of the lumber of any walnut, however, is dependent on the speed of growth. The highest grades of walnut lumber are obtained from slow-growing trees which produce a very tight, dense grain. Walnuts grown in the Maritime Northwest, or other locations where they make high annual increments of growth, do not make the best grades of lumber.

All walnuts need deep, well-drained soil and an adequate supply of moisture. Their deep root systems enable them to draw on subsurface water, thus minimizing irrigation requirements.

Oaks

There are over 300 oak species in the world. Their acorns furnish an important wildlife food and at one time they were a food source for many native peoples. The oaks can be separated into two main groups, the white oaks and the black oaks (which includes the red oaks). Acorns from the black oak group contain high amounts of tannin and are seldom used for food. The acorns of the white oak group contain smaller amounts of tannin, which is removed by leaching. One of the oaks most frequently suggested as a source of edible acorns is the burr oak (Quercus macrocarpa), a native of eastern North America. The acorns of the Garry or Oregon white oak (Q. garryana) were widely used by the Northwest natives. There are oaks which can be grown for various Northwest climates to produce fodder for livestock and quality timber.

The cork oak (Q. suber) can also be grown in the Northwest, as is demonstrated by specimens in Seattle and Portland. Its bark is a source of cork and it provides an edible acorn as well.

Beechnuts

Beech trees are native to both Europe and eastern North America. The small nuts offer little promise for human food, though they have been used for producing an edible oil. They do have value as food for hogs, domestic fowl, and other livestock and wildlife. They are adapted to shallow, wet soils.

The Future is Abundant A Guide to Sustainable Agriculture