By Roberta Bailey
The wild nut forests of North America are gone, having succumbed to weather, blight, and the heavy harvesting of their valuable lumber. No longer can families go into the woods and gather burlap sacks full of nuts for winter keeping. Yet many nut trees are hardy in the northeast, and a few nut trees can produce bushels of nuts. Chestnuts, filberts, filazels, hazelnuts, tree hazels, ginkgo, hickory, nut pines, heartnuts, buartnuts, butternuts, black walnuts, and many oaks, including the edible, acorn-producing burr oak, can be grown in the Northeast.
Space is a consideration with nut trees. With the exception of filberts, hazelnuts, and their various relatives (which reach 7 to 15 feet), nut trees will mature to 50 feet tall and close to that in width, more than most suburban lots can accommodate. Another consideration is that butternuts and black walnuts emit a toxic substance (juglone) that prevents many plants from growing underneath them. Conifers are particularly sensitive, but grass and blackberries are not. A large yard or a few acres can accommodate nut trees. Most nut trees need a pollinator. Single black walnuts, butternuts, and shagbark hickories can produce nuts, but will yield more if a second tree of the same species is planted within 100 feet. The flowers are pollinated by wind.
Less breeding has been done with nuts than with other fruits, but excellent cultivars are available. Nuts can also be planted from seed. Intentional crosses of choice trees have produced cultivars with especially large or flavorful nuts, or high yields, or nuts that crack more easily, or, in the case of American chestnuts, potentially more blight-resistant cultivars. In Maine, where hardiness is a consideration, one might opt to plant seed from a hardy Northern tree instead of purchasing an improved nut cultivar that may not be as cold hardy. On the other hand, if the species you want to plant is reliably hardy in your area, you may want to go for the selected cultivar. Cultivars tend to bear a few years earlier than seedling trees, which may take 8 to 10 years to bear. If you are planting all cultivars, rather than seedlings, chose different cultivars of the same species to pollinate each other. Two of the same named cultivar will not pollinate each other, because they came from the same tree, essentially. Each seedling tree is genetically different, so two walnut seedlings could pollinate each other.
To start a nut tree from seed, gather sound nuts from a tree with favorable traits. The nuts can be planted directly into a garden or nursery row and covered with a few inches of soil. To protect against squirrels, the seed should be covered with hardware cloth or metal screening, which must be removed before nuts sprout in spring. Nuts can also be overwintered in a plastic bag with moist leaf mold, sphagnum moss or potting mix. They need to stay moist. Plan them out as soon as the ground can be worked. Nuts will sprout over the next few months. If sprouting has occurred before transplanting, be extremely careful not to break the delicate tap root.
Planting a nut tree is similar to planting most fruit trees, except that they need plenty of space, away from driveways, sidewalks, roads and overhead wires. Nut trees grow best in deep, well-drained soil on a sunny site with some wind protection. Dig a hole large enough to set the tree to the level at which it grew in the nursery and a few feet wider than the tree roots they are spread out. Place the best soil in the bottom, around the roots, mixing in a small amount of compost if the soil is poor, and gently tamping to eliminate air pockets. Continue to fill the hole, ending by making a slight rim of soil around the hole to hold water. Water your tree thoroughly at planting and provide at least 1 inch a week for the first year when rain doesn’t do the job. Trace minerals, such as azomite, menafee humates or compost, can be spread around the surface of the planting area, then covered with a thick organic mulch.
Once established, nuts need little care. Spread a thick layer of compost out to the drip line each spring. Prune the trees to one central leader and, eventually, to have no branches for the first 8 feet. Diseases and insects seldom infest backyard nut plantings.
Harvesting and Curing
The years of watching your trees reach skyward will fly by, and a year will come when you notice nuts, actual nuts on your trees. Once fall comes, you can wait for them to drop and readily gather the nuts before they deteriorate quickly on the ground. If squirrels are a problem, shake the trees and gather the nuts. This process may take a few harvests.
Nuts need to be dried or cured before their meats ripen enough to eat. Spread them out one layer thick on screens or in the barn, attic, garage or greenhouse. You will need to protect against squirrels. Turn the nuts so that they dry on all sides. Depending on the nut, curing takes two to four weeks.
Species to Grow
Black walnuts, Juglans nigra, generally are hardy to zone 4, with some strains hardy in zone 3. They have a distinct, nutty flavor. The seedlings have very hard shells and thin nutmeats, but some hardiness is lost in softer shelled, meatier cultivars. The trees produce excellent wood, and the nut hulls make a rich brown dye.
Butternuts, Juglans cinerea, are quite hardy into zone 3, and their oily nuts are absolutely delicious. Cultivars have larger nuts with softer shells. Lewis Hill says wild butternuts shell easily if you pour boiling water over them and allow them to sit for 15 minutes, then drain and dry them. One easy hammer blow will pop the halves apart intact. Trees tend to bear heavily, then take a year to three off.
Buartnuts are a cross between the Japanese heartnut and the butternut, combining the butternut’s hardiness with the heartnut’s easy shelling, larger nutmeats and disease resistance.
Hazelnuts (Corylus americana) and filazels, which are filbert-hazelnut crosses with larger nuts than hazelnuts, are hardy in zone 4. They both bear sweet, round, filbert-type nuts. Filazels reach 10 to 12 feet and turn gold to orange and red in fall.
Although hickories are supposed to be hardy only to zone 5, I know of two shagbark hickories (Carya ovata) growing in central Maine. If you can plant seed from Northern trees, your chances of eating homegrown hickory nuts are fairly high. These large, moisture-loving trees produce a gumball-size nut within a thick husk.
Not sure what to do with those back acres? Consider planting a few nut trees, or a stand of trees that will mature into a valuable stand of lumber for a future generation – giving nuts in the meantime.
Nut Growing Ontario Style, a publication of the Society of Ontario Nut Growers, 1993. 172pp. Available from Fedco, PO Box 520, Waterville ME 04903-0520 (order deadline April 13, 2001).
Fruits and Berries for the Home Gardener, Lewis Hill. Storey Books, 1992. 266pp.