AMES — Several species of trees in Iowa produce edible nuts, which can be cheaply and readily harvested. Walnuts, chestnuts, pecans and hazelnuts can be collected and eaten. These nuts, when harvested locally, may offer a unique flavor distinct from their grocery store counterparts. In this article, Iowa State University Extension and Outreach commercial horticulture specialist Patrick O’Malley explains the process of collecting tree nuts in Iowa.
Chestnuts
Chestnut trees can be identified by their canoe-shaped, toothed leaves, large size and spiny seed pods, called burrs. These burrs contain chestnuts, which generally ripen in September.
Chestnuts should generally be harvested as burrs begin to swell and open, but harvesters must work quickly to avoid competition from birds, squirrels and other hungry animals. It is best to collect fallen chestnuts from the ground, as harvesting from the tree or shaking the tree may cause immature nuts to drop.
It is important to wear gloves while harvesting chestnuts, as the burr spines can puncture the skin. Ripened chestnuts (with a split open burr) should be harvested immediately; after about three to four days at room temperature, these chestnuts can be stored in the freezer and enjoyed for up to a year after harvesting.
Walnuts
Black walnuts are native and can be found across the state. Some people in southern Iowa have planted English walnuts and heartnuts. Butternut used to be found across most of the state, but a fungal blight has reduced the population to almost nothing. While each of these has a distinct flavor, the process for collecting them is similar.
Walnut trees (and relatives) can be distinguished by their large leaves, which may have between five and 25 leaflets. Walnuts can be harvested either by collecting dropped fruit from the ground or by shaking the tree. Generally, dropped fruit is ready to eat, but it is important to check the color of the nut to ensure ripeness. Ripe nuts should be a yellowish-tan color, while unripe fruits will still be green.
When harvesting and husking walnuts, it is important to be mindful of the dark stain they produce, which can damage clothes and stain the skin. After husking, this stain should be rinsed off using a hose. Then, the walnuts should be left to dry for two to three weeks, after which they can be stored or cracked and eaten.
Hickories
Pecan nuts are a type of hickory. The pecans grown in southern Iowa are smaller than conventional store-sold types but can have good flavor.
The other types of hickories harvested in Iowa are the shagbark and shellbark hickories. Because hickory trees are in the same family as walnut trees, they are similar in appearance. However, hickory trees can sometimes be a little larger. Shagbark and shellbark hickories are incredibly distinct, with rough, peeling bark.
Hickories are usually harvested in October or November, and the harvesting process is similar for all Iowa species, although shagbark hickories tend to have smaller nuts with thicker shells. Typically, ripe nuts will fall to the ground in their shells. They can also be shaken from the tree. Once collected, the nuts should be left to dry in their shells for two weeks, at which point they can be cracked and eaten.
Hazelnuts
The American hazelnut or American filbert, which is native to the Midwest, grows as a multi-stemmed bush rather than the traditional European tree. Still, these nuts are tasty and easy to harvest. Hazelnuts can be harvested from August through September and tend to be much smaller than their European counterparts. The nuts are held in distinctive fringed leaves and look somewhat similar to acorns. The hazelnuts can be harvested easily and eaten raw or used in cooking.
Harvesting wild-grown tree nuts is a great way to experience the bounty of nature this fall and appreciate Iowa’s unique biodiversity. For more information on Iowa tree nuts, visit the Iowa Nut Grower’s Association at https://iowanutgrowers.com.