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 shipments 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.
Now, just for these Carpathian strains it seems to me that we have pretty well--perhaps you might say--licked this question of winter cold; that is, at least down to perhaps 30, 35 below zero Fahrenheit, but we certainly haven"t licked the problem of early vegetation. That is, it starts out with warm days in the spring, the shoots get about this long (indicating), you get temperature going down to, say, 26, 27, 28, and your shoots are all killed back and you have lost your year"s crop. So that"s the problem which in the selection of varieties for this northern country, we have got to keep in mind, as I think that"s one thing to look for among your Carpathian trees. It"s one which will mature its foliage in the fall fairly early and which does not start out too quickly in the spring.
Now, we know there are some that don"t start out in the spring, like these Chinese types, but what we want is a combination of short-season, late-starting, winter-hardy walnuts, and I think we can find them if we keep at it.
I didn"t start out to talk so long, but I thought that was perhaps a sort of a summary of some of these things which we are looking for.
DR. CRANE: I"d just like to make a few comments. There is one thing that you have got to be very careful about, I think, in watching for these late-blooming Persian walnut trees that start in to grow, in Oregon, particularly, although the same thing is true in some areas of California where we are growing large quant.i.ties of Persian walnuts. You know that a deficiency of boron will cause trees to go into a condition which the growers out there now call "sleepers." They will stay dormant for quite a long period of time in the spring before they start growth.
That"s due to a severe boron deficiency.
Now, we have a lot of boron deficiency here in the East, and in areas in which we have trouble with growing vegetables, like cauliflower that has a hollow stem, or beets or turnips that split and crack, or where we have so-called drouth spot or internal corking in apples, you can be sure that you can"t grow a Persian walnut, because the boron requirement alone is many, many times that of an apple or of most vegetables.
In Oregon on the same soils where we are growing apples, we put on a half a pound of borax per tree to control boron deficiency on apples. On walnuts we have to use anywhere from five to ten or twelve pounds for a tree of the same size. We have to have a boron content in walnuts very, very much higher than that of apples. We have got to be careful about that.
So if you do find late-sleeping walnut trees, or walnut trees that are late in starting to grow, you will probably find that is a result of boron deficiency.
MR. CORSAN: Mr. Chairman, I visited the Pomeroy Nursery in 1934. I had, in my own planting, about a score of trees and they were a most amazing sight. The big trees were all seriously damaged by that 1933-34 winter, as were all Ben Davis apple orchards. So what amazed both of us was the fact that Pomeroy"s young trees weren"t dead.[2] Of the Pomeroy, all the big trees were dead. I ordered some more from him, and I planted them, but the trees froze down to the ground. Just as a very few varieties of the Crath Carpathians did. They froze twigs and they froze buds and sometimes they froze the trunk. Only a couple of Carpathian varieties froze down to the ground, but every one of the Pomeroy did. I was quite sorry, because I had a Chinese English walnut from North China that was extremely hardy and lived through that winter almost undamaged. The nut, though, had a bitter tang, and Pomeroy"s nuts were quite sweet and delicious, but I haven"t a Pomeroy on the place. They are all stone dead.
[2] See Mr. Gellatly"s paper in this volume.--Ed
DR. MacDANIELS: Thank you, Mr. Corsan.
Mr. Harry Weber will give us a paper by Gilbert Becker on Persian and black walnuts in Michigan.
Grafted Black and Persian Walnuts in Michigan
GILBERT BECKER, Climax, Michigan
The performance of grafted Persian walnuts in southwestern Michigan has been so satisfactory that I would not hesitate to recommend them, in preference to grafted black walnuts. One of the nicest things about grafted Persian walnuts is that when they start to produce nuts, they bear _every_ year--there is not an off-season, as with the black walnut.
Our locality may be especially suitable to them. Our skies are cloudy, and it is cool through much of the spring, thus preventing early growth before conditions are right for the buds to develop unhampered by late spring frosts. We have had an occasional late freeze that caused the lower nuts to drop, while the higher ones remained on the tree, unharmed.
In this article I would like to answer briefly our most often asked question, as to which varieties do we think best from our experience with them? Our climate must be quite different from that found around Ithaca, New York, because we have never had winter injury in certain Persian varieties, as occurs in that area. (And we had 26 below zero in February, 1949.) An instance of this difference is in regard to the McDermid variety, which happens to be our choice. We honestly believe the Crath No. 1 variety to have great commercial possibilities, because of its heavy production of large, thin-sh.e.l.led nuts, of average quality.
The Broadview is another. The Carpathian "D", apparently, pollinates the Crath No. 1 well. This one, however, is small, with a very white kernel that is sweet. We have many other varieties producing, some with their first crop this year; but we are not able to recommend any of them yet.
The black walnut varieties must be rather limited, because of the brooming disease trouble; so we select from those that are quite able to resist it, or that seem immune to the trouble. The Thomas and Grundy varieties lead with us, and two other local nuts, the Adams and the Climax, rate high in our estimation. We have some nice grafts of the Homeland bearing their third crop, which we like very much, and they appear disease free. The Elmer Myers, Michigan, and other varieties are now badly affected with brooming disease.
Several years ago I reported on my observations on the brooming disease.
Now, I wish to report a little more upon the subject, especially in regard to how certain varieties have withstood its ravages. I hesitate to make any estimation as to how prevalent the disease is in the wild black walnut today, for it could be quite a controversial subject, with some claiming I was very wrong. Anyway, many of our native walnuts are now affected. Outward appearances are often very deceiving; but, when one cuts the top off a seedling and attempts to graft it, he may be amazed at the broomy growth that soon appears from the stock, should his graft fail to take. Trees that appear healthy, but have made slow or poor growth are often affected. Short, twiggy, upright growth that soon becomes dead or partly so, and arises from the main framework of an apparently healthy tree, is one of the signs that disease is there.
I have claimed there are two, or possibly, three forms of brooming disease, and I am still as convinced as ever. The so-called "witches-broom," as commonly seen in the j.a.panese walnut, is the form most people seem to think of. The second form is the rapid-growing type, that lops, or arches downward, is gray or green in color of wood, is very brittle and easily broken in the wind, ripping off good sized limbs, and winter-injures badly. An investigation, will, however, show much dead wood comes before severe weather. This form has some broomy, upright growth, like the first, but it is never bunched. The other, or possibly, the third form, is the latent type that doesn"t seem to do much harm, merely causing poorly filled nuts. The latent form is difficult to note, and can be detected only by the many short, dead, or partly dead, upright twigs scattered along the main framework of older trees. Cutting off part of the top will cause the typical growth to arise, thus identifying itself.
Early observation showed that certain walnut varieties were almost unaffected, or could even be immune, to the brooming disease. Different limbs of a large tree were topworked to the Thomas and the Allen varieties of black walnut. The Allen "took" the disease at once, while the Thomas grew thriftily and has always produced good crops of nuts.
Later, the Calhoun variety was grafted on some lower limbs, and has remained healthy. The diseased Allen grafts are still in the tree, are now 15 years old, and are more or less alive, but in very poor condition, with the signs as found in what I call the latent form. In 1938, the McDermid Persian walnut was grafted into this same tree, and its grafts produced good crops of nuts.
I wish to cite another instance of how little the Persian walnut is affected, regardless of variety. In 1938 a large black walnut near the house was grafted with Persian grafts, on stubs that had failed the previous year. The tree had the second, or rapid growing form, of brooming disease. I have pictures showing how badly the 1938 grafts took the rapid growing form of growth; while two 1937 Persian grafts showed no signs of trouble. The tree started to bear in 1941, and has made remarkable growth. It is now one of the nicest Persian walnut trees I have, bearing heavily every year. It is about 30 feet tall and 20 feet broad, with no apparent signs that it was ever affected.