Part 9 (2/2)

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.

<script>