The Carpathian walnut has proved hardy to sub-zero winters and is doing well in the Midwest and the northern United States, where California varieties suffer catastrophic winter injury. The glossy-leafed, white-barked trees and their early ripening nuts look just like those from California. When ripe, the thin hull splits, dropping the nuts to the ground.
This hardy strain was introduced in the 1930s by the Rev. Paul C. Crash, a Canadian missionary to Polish Ukraine. He purchased seed from select trees which stood 40° degrees Fahrenheit below zero temperatures in the Carpathian Mountains of Poland.
The source was shipped to Canada and sold in the United States to defray purchase and shipping costs. People living in almost every state in the union purchased seed nuts from the Wisconsin Horticultural Society.
The trees, it was found, usually did not do well in the southern states but proved they could take the rigors of the Midwest and still produce an annual crop.
Contests, held to select the best of the Carpathian trees for grafting on their own or black walnut seedlings, have uncovered other hardy “English” walnuts. (The species is Juglans regia. Nuts were first shipped to America in English ships. The correct name is Persian walnut or just plain walnut.)
Trees From Seeds
Many appear to have been trees grown from seeds sent by Germans, Hungarians, and Rumanians to relatives in the northern United States.
One of these looks very promising is the thin-shelled ‘Hanson’ from northern Ohio. `Manregian, now being tested in Maine and Michigan, originated at Salem, Oregon, from seed from Manchuria. Carpathian varieties now being sold as grafted trees include ‘Fickes,’ Colby,’ Helmle 8′ and others.
The ‘Colby’ Carpathian ripened over two bushels of clean nuts (they drop free of the hull) in 1956 at the University of Illinois. I was 20 years old. With proper pollination, a nursery-grafted tree should bear a few nuts in three years, and the crop should become progressively more prominent as the tree grows.
This is sooner than black walnut trees or standard apple trees commence bearing. There are reports of older trees (over 50 years old) of German origin bearing in the neighborhood of ten bushels.
The success of the Carpathian strain has led some experiment stations and state universities to plant seeds from other cold climates, such as the mountains of Afghanistan and Kashmir. Some of these grow in Cheyenne, Wyoming, where the native black walnut fails.
Walnuts in University of Illinois
Some good seedlings of second-generation foreign walnuts are beginning to bear at the University of Illinois. The seed came to Illinois from the United States Plant Introduction Garden at Chico in northern California.
Since the trees at Chico probably crossed among themselves, it is impossible to say if a seedling at the University of Illinois is purely Estonian or Afghanistan. Seed parentage of these second-generation trees includes India, Afghanistan, Pakistan, Iran, Poland, and the Baltic states.
While the native black walnut tree takes an upright form, the Persian walnut takes a fruiting shape. Unpruned, it grows oval or round like a ball. Eventually, the lower branches will be shaded out and die if they aren’t already pruned off.
Growing Nuts
Recommended spacing would be 50’ to 60’ feet to allow for future growth. Nuts planted in the late 1930s are now trees approaching 30’ feet tall and are nearly as broad. They tend to grow taller when squeezed by barns, bushes, houses, garages, and other obstructions.
This clean species makes a fine landscape tree for the front yard where space permits. It is generally free of fungus diseases which cause early defoliation of many native black walnut trees. It is very tolerant of soil conditions and does well in poorer soil than the native black walnut trees. However, frost pockets or low spots are to be avoided.
Since it is tap-rooted, large specimens are difficult to move. It will not seek out and clog sewers, nor does it rob the lawn of all plant food like many surface-rooted shade trees. For a home or farm, it is a specimen of which to be proud.
44659 by Clarice Hickox