Part 9 (1/2)

Prospects for Persian Walnuts in the Vicinity of St. Paul, Minnesota

CARL WESCHCKE

Although I was asked to prepare a paper on the Carpathian walnut, I feel that my other experiences with Persian or so-called English walnut (the botanical name of which is _Juglans regia_) are also of some value to those who might be tempted to try this species of walnut in cold climates.

When I first started my experiments with nut bearing trees, I included the English walnut among the possibilities for our section. Mr. J. F.

Jones of Lancaster, Pennsylvania, gave me much information and a great deal of help in trying out what he considered hardy strains. There was a walnut tree in Boston, known as the Boston walnut, of which he sent scions, and which I grafted on b.u.t.ternut. This was about the year 1920, and was included in my grafting experiments together with black walnut, heartnut, hickories, and hybrids between hickory and pecan. Later on, he sent me scionwood from other known hardy varieties which I placed on b.u.t.ternut, and many of these made tremendous growths but were winterkilled the very first winter. None of the English walnut with which I continued experiments lived over the first winter until I received scionwood from Prof. James Neilson of Canada, who sent the Broadview. These Broadview scions were grafted on b.u.t.ternut and black walnut, and a few of the scions survived for possibly three seasons, even producing staminate and pistillate blossoms and small nuts which grew only to about the size of a quarter and then dropped off.

Clarence A. Reed arranged to have some small seedling Chinese strain of _Juglans regia_ sent from Chico, California; these were planted in favorable places and survived a few winters. I also planted seeds of the Chinese strains which gave me no better results than the seedlings.

Then I bought walnuts from A. C. Pomeroy, of Lockport, New York. These were even more tender than other varieties with which I had experimented, although they were very much publicized by Mr. Pomeroy in the Nut Grower during that era as being extra hardy, because they were growing near the south sh.o.r.e of Lake Erie.

I next went to Mr. Jones, who was then selling quite a quant.i.ty of Wiltz Mayette and Franquette strains of English walnut grafted on black walnut. These proved to be among the most tender varieties I have ever tested here. Then he sent me scions of the Hall and Holden varieties, which he felt were considerably more winter hardy, but here they failed to survive even one winter.

We have not neglected the Rush English walnut either, which was tested in a similar manner without any good practical results.

This now brings us to the convention at Geneva, New York, in 1936 when the Rev. Mr. Crath and George H. Corsan presented a new strain of English walnuts, known as the Carpathian strain, originating in the Carpathian mountains in Poland. This so impressed me that after talking it over with my father we decided to finance a trip into the same region that Mr. Crath had been in, to locate new and better varieties for a real test. The story of the Rev. Mr. Crath's and my adventure along these lines, during the winter of 1936-37, has been printed in the records of the Northern Nut Growers a.s.sociation, and I will bring out only the high spots that seem to be important 14 years later.

In the s.h.i.+pments of hardy material collected were some 4,000 scions of possibly a dozen different good strains of what Mr. Crath considered hardiest and best. In addition to that, there were around 500 trees ranging in size from small whips of one foot long to some that were over eight feet; also there were some 400 pounds of nuts to be planted to produce seedlings.

These nuts had been gathered from superior hardy trees with the expectation that the seedlings would produce nearly true imitations of their parents in the quality of their fruit and hardiness. These seedling nuts produced somewhat over 12,000 seedling trees, which were planted in about six large strips of land so as to give room for cultivation. The 500 trees received from Poland were planted in favorable locations and many of them are still alive. The scionwood was put on native b.u.t.ternut and black walnut. Some of it was grafted to young nursery stock, but most of it was put on large mature trees, being top worked. Grafting was started in April and continued into the early part of June. The later grafts were much more successful than the earlier ones, although some of the April grafts grew and flourished.

Many of these grafts bore flowers and had little nutlets but none of them ripened nuts. After about three seasons some of the grafts that continued to live produced a few nuts.

Three varieties were practically mature, and then the native insect pests caught up with them. Also, there was a black rot or wilt which I am fairly sure was walnut bacteriosis disease, although specimens sent out to competent authorities did not corroborate this diagnosis. What turned out to be the b.u.t.ternut curculio attacked all grafted and seedling trees with such vigor that there was no way to combat it. I sprayed some of the grafted specimens and kept it up for several years, trying to hold on to them, but it became too much for me and my equipment; I doubt now whether any amount of poison would have saved the trees because the b.u.t.ternut curculio is difficult to kill with poison.

One of the varieties, known as the Kremenetz, grafted on black walnut, was sent to Harry Weber. It thrives and bears nice crops at his country estate in Cleves, Ohio, near Cincinnati. He has sent me scions of this variety, and this spring I grafted them back on black walnut, as the b.u.t.ternut curculio is not nearly as bad as it was when there was so much English walnut foliage for them to feed on (this foliage is their choice over all other foliage). These insect pests also wiped out several heartnut varieties which came from J. U. Gellatly, of Westbank, B. C, Canada; for next to English walnuts the curculio loves heartnut foliage and its new branch growth.

We have about 60 to 70 acres of woods which contain a large percentage of b.u.t.ternut, therefore it is next to impossible to wipe out their native food. I doubt very much whether this would have benefited the situation at all, as the curculio would have then centered all its activities on the English walnut foliage and perhaps have attacked hickories, pecans, and black walnuts, on which they sometimes try their appet.i.tes. Hybrids between b.u.t.ternut and black walnut are viciously attacked by this curculio. Hybrids between English walnut and other species of walnut which I have here also become a prey to curculio. So there is no trick species which would be immune to their attack.

The English walnut usually vegetates too early in the spring to escape some of our late frosts. Because this new growth generally contains the flowers, the fruiting of such trees would be very unreliable and only occasional. We even have trouble with black walnut and b.u.t.ternut in this respect. The hickory is much better, and the pecan is even later in respect to vegetation. I mention this because even though everything had gone well it is doubtful whether reliable crops of English walnuts would ever have been produced from the so-called hardy Carpathian series.

A year or so following the experiment with the Carpathian walnut, I imported about 100 pounds of seeds from Austria. They came in two different lots: one of them was more expensive than the other seed, and it proved to be much the hardier. The larger lot of smaller seeds was not as hardy. Although we have several hundred trees of this better seed lot which remain alive, they are no better off in any respect than the Carpathian seedlings. In fact, I could not see much difference between the behavior of these seedlings and the behavior of the Carpathian walnut strain.

While in California in 1939 I picked up about five pounds of seeds from a hardy tree growing in the Sierra Nevadas in Sonora, also some native black walnuts. These survived a few years but finally were winter-killed entirely, root and all. The Carpathians are never killed out entirely but continue to grow from the root systems, even though they are frozen back to the ground; but the insect and the fungus have destroyed many thousands of the original group of trees so that there are today perhaps between 1000 and 2000 living trees, which sprout up each spring and kill back each fall with clock-like regularity. Among these; However, are a few outstanding varieties which extend some hope that there may be among these survivors one or more trees which resist the b.u.t.ternut curculio and have become acclimated, to such an extent that they do not entirely kill back but only a little of their new growth is killed. These specimens usually are the ones that make a shorter growth during the summer, in fact have more of a tendency to be a genuine dwarf type of tree. Three such seeding trees were known to have sprouted from exceptionally large and very thin-sh.e.l.led walnuts, which I believe the Rev. Mr. Crath calls the giant type.

I will now summarize and express my own private opinion regarding the future possibilities of introducing the English walnut into such an extreme northern lat.i.tude as we are in. First, experiments started thirty years ago, which period gives a reasonable period of time that any man should feel is necessary to devote to giving a species a try-out. Secondly, we have used material from every reasonably known source. Third, persons in charge had a reasonable amount of skill and success with other varieties to have insured success if the material had been responsive. My opinion, for what it may be worth, is that the species is out of its range in this northern lat.i.tude, more particularly because it is too tender to fight its own battles as to insect life which attacks it, particularly the b.u.t.ternut curculio. Gra.s.shoppers, leaf eating insects, and worms of different sorts, also attack it more than they do other nut tree foliage. The possibilities of a break in the strong cycle of insect life is a hopeful prospect which we are helping by breeding tens of thousands of toads and frogs. This might allow some, of the more vigorous specimens to acquire sufficient size to overcome this weakness. In my opinion, the climate itself is not the main governing factor which would kill out all hope of raising English walnuts here; but certainly, coupled with the disastrous attack of insect life and susceptibility to blight, these three foes are almost insurmountable. And then in view of the early vegetating habit of these species, there is the possibility that even though you had a hardy tree, immune to insects, you would never get much fruit.

Discussion

DR. MacDANIELS: Remember, the climate up around St. Paul is a bit rugged, and I think that work of that kind is certainly of value to give us an idea of the limits at which we can grow these trees, but I don't think that we have by any means explored the whole field.

In the Morris collection at Ithaca there is a little Persian walnut about the size of the end of this finger (indicating), a very small nut, that was given to Dr. Morris by a consul from the interior of Asia up in the Himalaya Mountains in Tibet, from of an elevation of about 10,000 feet. That little walnut had a hard sh.e.l.l, harder than some of our sh.e.l.lbark hickory nuts, and a bound kernel that I would say was much less promising than many of the nuts which we discard.

Somewhere, it seems to me, in this vast range of material we ought to be able to find some variety or clone of these species that would be adapted to practically every part of the United States. There at Ithaca we have the difficulties with the Persian walnut mainly of winter cold.

That is the absolute low temperature that wipes out the trees, now that I have seen them come and go in my place there and in the vicinity. The old Pomeroy strain is killed at about 20 below zero Fahrenheit. It stayed there in fairly good condition up in the Lockport region until the extreme cold of 1933-34. Once the temperatures went down to nearly 30 below zero, except for a small region around the Niagara peninsula, where it hit only 12. Those trees are still there in that little circ.u.mscribed area around Niagara, and we saw a picture of one of them in Mr. Sherman's collection. But the Pomeroy trees, I have learned--I haven't seen them myself--were practically wiped out, as were the others, in what was thought to be the protected area along Lake Erie.

I remember the trees on the Whitecroft farm along Keuka Lake. Some of you saw those when the Nut Growers a.s.sociation met at Geneva. They are on a bench close to Keuka Lake, which up to 1933-34 had not been frozen over for many years. They had grown, produced good crops, were in excellent condition, but that year the temperature went down to about 30 below zero and stayed there for a number of days. The lake froze over, and the trees were severely damaged. A California redwood which was there--had been there for 80 years--was killed outright, and so it goes.