Part 9

A nut tree nurseryman has experiences that are both pleasant and unpleasant in selling trees as well as producing them. This is probably well known to all of you who have produced and sold nut trees. It is astonishing how many questions (some of which are amusing) the public can ask, and very often those that ask the most questions, leading one to believe they are a good prospect for a large order, may order only one or two trees, or none at all. Then there are those who have never bought a nut tree before, and when they see their first one are dissatisfied because it does not have a root system like a fruit tree; and there are a few who will try to get replacements whether they are entitled to them or not, and usually they are not; for, regardless of the instructions given for the planting and after-care, they will neglect them, then complain if they have a loss, and certain experiences have led me to believe they claim loss before having it.

Many seem to think that a nurseryman should guarantee his trees to live when planted by the purchaser. To do this would be assuming the responsibility of the handling, planting and after-care of the planter, which would make it necessary for the nurseryman to put a price on his trees that would take care of a lot of replacements to the more careless ones who would have losses, and be very unfair to those who take good care of their trees, and have little or no loss, as they would be standing part of the loss of the careless ones.

The most a nurseryman can do is to produce the best trees possible, dig them carefully, pack them in first class condition and ship them immediately.

Discussion after Mr. Wilkinson's paper.

Dr. Crane: "Minor elements are important in plant nutrition The problem of deficiencies is going to become very important. We do not keep the livestock we did and we are not returning to the land the manure and other fertilizers that contain the elements the trees need. Nitrogen, phosphorus, and potash, also magnesium are needed. We are taking more from the soil than we are putting back."

Corsan: "In Cuba there are hundreds of sharks. These make fine manure, wonderful for nut trees."

Prof. Slate: "How many sharks would you need for an acre of land?"

Morphology and Structure of the Walnut

C. C. LOUNSBERRY, Iowa State College

This subject, the structure of the walnut, is discussed in its relation to propagation. Catkin bearing nut trees, such as the walnut, have a refined structure that makes grafting difficult. Structure, rather than form of walnuts, suggests treatment under the headings, bark, cambium, wood, roots, pith and buds, as well as the sap that permeates them.

=Bark:= When the bark of the walnut is cut, as in budding, it is difficult to tie down so it will not curl and yet not strangle the bud. The wax-like covering of the bark is thin. However, the bark itself will stay green two months or more if weather is cool.

=Cambium:= The cambium dries quickly when exposed to air, and must be kept covered. Grafted walnuts show callus growth from the cambium, and also from the pith of stems and the endodermis of the root.

=Wood:= The wood of the walnut is diffuse porous, brittle, straight grained, and easily split. The wood must be cut diagonally to get sufficient tension to hold the scion in grafting. The branch grows rapidly in a short season, May 15th to July 1st in central Iowa. The upper two-thirds of the one year growth is usually light weight with pith of large diameter. The base of the one-year growth is the best for scions. Some varieties of walnut as for example the Thomas, have relatively large one-year growth and more scions can be cut from its branches than from the wood of Ohio which is small and willow-like.

Measurements taken in 1940 on 118 common black walnut seedlings planted in 1939 showed 9/16" average diameter of seedling at crown, 5/16" average diameter of pith at crown; 3/8" average diameter of seedling at top; and 1/4" average diameter of pith at top; 3.26 inches average length of solid pith above crown; 2.91 inches average length of solid pith in root below crown.

=Pith:= Pith in the black walnut is chambered (lamellate) in the older wood, but solid in the younger, growing wood. The plates are a light brown color, getting larger in diameter toward the top of the year's growth. The leaf traces from the leaf rachis to the pith show heavier from the bottom buds of the branch than at the tip, and the pith is usually solid at the bottom of the branch.

=Roots:= When the nut of the black walnut germinates in the soil the lobes or cotyledons do not rise above the ground like the cotyledons of the bean but remain in the nut shell under ground, and are broken off in the growth of the seedling, the root going down and the stem rising above the ground. Where the cotyledons are broken off, the so-called crown of the walnut, two rough places appear, nearly opposite on the stem. In these rough places, two groups of buds are formed, rarely three groups.

Cytological studies at Iowa State College have not shown why there are not stem initials in the tap roots of the walnut. When the root is cut off a foot underground, root initials develop but no stem initials. The sensitivity of walnut leaf buds to water may have something to do with it.

=Buds:= Buds of the walnut are in vertical groups of two or three in the axils of the leaves. They have few scales. They appear on seedlings and current year branches. Some have short stalks. If broken off they do not usually grow back again. The second year, these buds usually drop off in mid-season. In cutting off buds, unless the group of buds is taken out as a chip, some may grow out again.

=Leaf arrangement:= There is a three rank arrangement of leaves in the walnut, the ninth leaf coming in the same position as the first. According to the work of Caesalpino, the buds should then rise in three places at the crown. Only in rare cases does this occur in the black walnut, although it is usual with the Persian walnut. If the nut is planted deep this causes much suckering and a tendency to etiolate the buds so they will stand water.

=Buds are sensitive:= Buds are sensitive to water, and storage material must be fairly dry and cool. In two large boxes of scions received last year from Germany, some 20 varieties of Persian walnut, all had dead buds when received. They were packed in German peat. When buds are covered with wax the wax must not be too hot or it will kill the buds. In placing grafted walnuts in sphagnum or sand they should not stay wet or the buds will die. Either unions must be above damp sand or sphagnum, or the buds be protected by wax or adhesive.

=Sap:= In spring grafting there is an enormous flow of sap which will sometimes tear the plates out of the pith. Grafts may be protected by girdling the stock a few inches below the place where the graft is set, or both above and below it. In 1937 259 walnuts three years old were cut off six inches above the ground and girdled two inches above the ground. 171 crown buds came up, 88 started above the girdling. 207 trees were cut off three feet above the ground, and the trunk girdled six inches above the ground. 153 started above the crown, and 90 started above the girdle. The same year (1937) 195 trees three years old were cut off four feet above the ground, and all buds above ground were cut flush with the surface of the bark. This was repeated twice, finally taking buds out as a chip, except the top bud; 126 died; 69 grew from the top but. 203 trees three years old were cut off five feet above ground and all buds cut off except upper one; 64 died; 139 grew from top bud. 200 trees three years old were cut off six feet above ground, and all buds kept rubbed off except top one; 33 died, and 167 grew from top bud.

=Vitality and sap:= Black walnut sap changes color from oxidation almost instantly. Bench grafts must be made quickly and put in place at once or the unions will dry out. If the root does not stain hands in grafting the graft usually fails. In outdoor grafting if the sap stands in pockets the sugar will ferment, killing the graft. There is a new Jersey (3) bulletin which shows black walnut sap as unstable, quickly forming sugar when exposed to warm weather.

=Vegetative propagation of greenwood cuttings:= Witt and Spence (4) in England working with greenwood cuttings attained 75 per cent success with Persian walnut and Royal walnut in July and August. They had no success with black walnut at that time (1926). The Germans in 1936 (1) working on greenwood cuttings had most success with the Persian walnut, but used greenwood taken in September.

=Vegetative propagation or hardwood cuttings:= In 1938 the author (2) using growth substance on saddle grafts of various walnuts found Asiatic and western walnuts went on their own roots. At this time the Tasterite black walnut went on its own root. In 1946 and 1947 using about 25 varieties of black walnut, Persian, western and Asiatic walnuts, eight inch hardwood cuttings were used beginning in December and repeated in the spring of 1947. Nearly all the cuttings of the larger size (about 1/2") started in about a month and grew about two months. Then all died. There were balls of callus on many of them. One on Thomas was an inch in diameter. The bottom heat was held at 70 degrees F. This may have been too high, as on raising the cuttings it was found the callus had rotted. This procedure has possibilities.

Literature Cited

1. Institut fur Obstbau, Berlin. Die Walnusz veredlung. (Vegetative propagation of walnuts). Merkbl. Inst. Obstb. Berlin 5, pp. 15, 1936.

2. Lounsberry, C. C. Use of Growth Substance in Bench Grafting Walnuts and Hickories. Northern Nut Growers Association 1938 Report, p. 63.

3. Nelson, Julius. Fermentation and Germ Life. N. J. Ag. Exp. Sta. Bul. 134, 1899.

4. Witt, A. W. and Howard Spence. Vegetative Propagation of Walnuts. Ann. Rep. East Malling Res. Station 1926-27.

A Method of Budding Walnuts

H. LYNN TUTTLE, Clarkston, Wash.

It took man some thirty thousand years to learn to build a fire--conveniently. I thought it was going to take me that long to learn how to bud walnuts, but fortunately the period has been somewhat shortened.

When I first began to propagate, or try to propagate, walnuts, I naturally looked to the approved and accepted methods. For me, they did not work. Before I was through I think I tried them all. I patch-budded with variations and improvisations. I shield-budded and bark-grafted. I coated the wounds with grafting-wax, latex, cellophane, asphalt and paraffine. I trimmed off the bud shoulders to make a smoother tie and trimmed around the edges to make more contact. I wrapped with raffia, strings, rags and rubber strips and tacked with small nails. Whatever I did or however I did it results were all about the same--the sap soured. In fact over a period of years I tried every way I could think up or read about to bring the bud and the cambium layer together and make them stick. Results were surprisingly uniform--the sap soured.

But we must not dwell too long on the shots that missed. As with a refractory engine that will suddenly sputter, there came some elements of success. The point to learn was, why? Concentrating on the shield bud entirely we determined to find these whys. So we tried taking big slabs of bark along with the bud, peeling out the wood, breaking off the leaf stem entirely and waxing the scar and making an unnecessarily long cut for the bud. The bark stuck fairly well but the buds died. This was some encouragement and I knew that with enough time, reason and a little luck we would eventually hit the mark.

Now Dame Fortune had decreed that I be raised on a grain and stock ranch where the only trees we could see were in the distant mountains, or, if we rode in the canyons, cottonwoods and choke-cherries. My experience and training was with animals, and animals, especially horses, seem quite susceptible to accident. The first principle of treating almost any wound is to give it drainage, otherwise, both literally and figuratively, the "sap" soured. Thus it dawned on me that a tree-wound, even if only skin deep should have the same treatment as a flesh wound. And drainage, being desirable, should be ample.

It was quite late in the season but I went out and set a dozen Schafer walnut buds on eastern black stocks. These buds HAD DRAINAGE. The vertical cut of the T extended at least two inches below the bud. Success ensued, they grew. The following spring we budded as soon as the bark would slip and continued at intervals all summer. Results were good. Some of the steps we now use are probably not essential and perhaps not even the best, but there are two points that cannot be over-emphasized, namely, drainage and contact. The complete method is as follows: 1. Trim bud sticks to leave an inch of petiole on the bud. 2. Make the T cut with a long vertical slash that will extend at least an inch below the bottom of the bud. 3. Cut the bud long and deep and peel it from the wood by pinching the sides. Be carefull not to injure the bark just below the bud. 4. Insert the bud either flush with or below the cross-cut. 5. Wrap with large sized rubber budding strips just firmly enough to make good contact. Too tight wrappings curtail circulation. Do not cover the cut below the bud. The wound must have =drainage=. 6. Be sure that the center of the bud-cut is firm against the cambium layer. If it humps of bows and won't stay down insert a tooth-pick or bit of leaf stem or something along the center line to hold it down. We usually do this during the wrapping process.

We use no wax. We throw a wrap over the bud, shoulders even though it may press the petiole forward against the bud. If the center of the bud pulls out it will not grow although an adventitious bud may eventually start. Budding seems about equally successful any time that the bark slips freely. On walnuts this is all summer if not too dry.

Early-placed buds may make several feet growth before fall if sufficient moisture is available. On walnuts there are always dormant buds. We have used storage wood but now just cut it fresh. We have not tried draining patch-bud or grafts. Although we have not tried it we think cherries and other trees inclined to drown the buds might be better handled in this manner. Climate is a factor in the type of propagation advisable. One very fine grower using buds in California could propagate only by grafts when he moved to Western Oregon.

The kernel of my walnut budding experience may well be summarized in one word--drainage.

* * * * *

Questions asked Mr. Stoke after his demonstration of grafting and budding. [See his paper in 1946 Report, pp. 99-103.--Ed.]

Member: "How do you keep your scions?"

Stoke: "I prefer 'orange' cold storage for scionwood. This is just above freezing. Walnuts should be in full leaf before spring budding."

McDaniel: "What percentage of chestnuts did well with the 'plate' method of budding?"

Stoke: "I don't use it with chestnuts for spring budding, but sometimes for summer budding. It will work well on any variety of Persian walnut, heartnut and black walnut. Place buds on the north and northeast side of tree to prevent sun injury."

Question: "Do you find any difference in using buds from an eight or ten year old tree as against a younger tree?"

Stoke: "No, not so long as it is healthy. For spring budding I don't care to have any trees too vigorous. Cut tops off young trees three to five days after budding, and force the buds into growth. If you delay too long the bud will die. I wouldn't try to bud trees unless bark is slipping."

Member: "I have used parapin wax and covered it with old bread paper."

Stoke: "That may work because the wax was shaded. Southern sun may melt parapin and paraffin waxes."

Mr. Corsan: "Dentists, surgeons and wood carvers make the best grafters."

Question: "Can the scions be cut with a small plane?"

Stoke: "Anything you have to cut with a plane is too big. I never use a plane."

Question: "What do you use a splice graft for?"

Stoke: "Anything except walnut. In walnut I use a modified cleft graft, and I take care of the sap flow by placing the graft down about 1" or 1-1/4" below the cut (where the tree is cut off). Wax the scion but do not wax the cut. Let it bleed."

Question: "What is the value of cut leaf black walnut?"

Stoke: "Purely ornamental. Weschcke reports that it is very hardy with him."

Rick: "What about the Lamb walnut?"

Stoke: "We don't know whether the wood of grafted trees is curly or not. I sent Mr. Reed a limb from Lamb and he gave it to the forest laboratory and they found no evidence of curly grain."

Rick: "Shouldn't it be propagated until we are sure?"

Stoke: "We had Mr. Lamb himself talk before us at Roanoke and he told us about the parent tree. He doesn't know what makes one tree curly and another not."

Korn: "Is that uncommon?"

Stoke: "Not so very. Trees are most curly at the base and in the outer wood."

Question: "Do you always leave that stub on black walnut?"

Stoke: "Yes, but it should be removed later in the first summer."

Question: "Where do you use your splice graft."

Stoke: "On anything other than walnut, if scion and stock are the same size. Where stock is larger than scion I use the modified cleft graft up to sizes approaching one inch in the stock. For topworking larger stocks I use one of the forms of bark graft. For the large hickory stock Dr. Morris' bark slot graft is preferred. For large, thin-barked stocks the simple bark graft may be used. My original grafts of the Carr and Hobson Chinese chestnuts, made with scions received from Messrs. Carr and Hobson in the winter of 1932, are still perfect unions.

"I believe that grafted chestnuts growing in frost pockets are most likely to develop faulty unions; possibly frost injury to immature cells at the junction point may occur. Dr. Crane mentions a similar failure of unions between Persian and black walnuts on the Pacific Coast."

Dr. Crane: "What cut did you use in grafting those chestnuts?"

Stoke: "Modified cleft. In using Dr. Morris' bark slot graft I find it best to leave just a little of the cut face of the scion wedge above the top of the stock. This, with top of the stock cut sloping away from the scion, as illustrated, promotes quick healing with no 'die-back.'"

Dr. Smith: "Is that top slanting?"

Stoke: "Yes, I cut it slanting."

Dr. MacDaniels: "That is a good graft for walnuts, too."

Note: Mr. Stoke showed the group a picture of a mockernut tree in one of his fields which he had girdled to kill it. The tree lived four years and during those years the moisture had to go up through the inner wood.

The substance of Mr. Stoke's talk, together with illustrations, may be found on page 99 of the 1946 report.

Importance of Bud Selection in the Grafting of Nut Trees

G. J. KORN, Kalamazoo, Michigan

For many years the fruit growers have been improving the qualities of their fruits in several ways. The early pioneers of our country selected the best fruits from seedling trees. Chance seedlings that were found in pastures, by roadsides, or possibly in some out-of-the-way place, selected because of some special quality or group of qualities, still dominate our commercial plantings of fruits and nuts. Several of the apple varieties to be found in the market today are from these chance seedlings.

In more recent years some of our agricultural colleges have been breeding fruits. Such breeding has given us several of our more promising named varieties. In this way a great improvement has been brought about in our fruits.

Environment too appears to have played an important part in making changes in fruits and nuts. Nuts that are extremely hardy in the more northern latitudes, appear to have developed this hardiness gradually throughout many generations. Because of this quality we are now able to select varieties that are most likely to succeed in any particular locality.

More rapid and satisfactory methods of improving our fruits and nuts have been brought about through breeding. This development of the science of plant breeding has made it possible to blend the good qualities of two seedlings into a new variety. Man does not have to follow nature's slow hit-and-miss method of developing more desirable qualities in her products. Controlled breeding, as brought about by man, produces faster and more satisfactory results. Man's improvement over nature has come about through his choice of the qualities to be blended, and his ability to bring together two parents from widely separated parts of the earth, if necessary.

Besides breeding, we are able also to use some of the mutations or bud sports to improve our nuts as well as fruits. Although our progress in improving nuts may not yet be as spectacular as cross-breeding with apples, bud selection has already modified the list of our commercial varieties.

One of the first requisites in bud selection is so thorough a knowledge of the variety that any departure from the type will be detected. Then it will be necessary to start propagation to determine whether the variation was caused by some environmental factor, or is really a sport which can be perpetuated by vegetative propagation. You may wonder if many of our nut growers know nut varieties well enough to detect any but the most obvious sports. Nut improvement through bud selection within the variety lies ahead of us.

Among fruit growers the search seems to have been for fruits of different or more pleasing color. As nut growers we are more likely to be interested in nut sports having better size, kernel, cracking qualities, etc. Trees that are able to ripen their nuts in short or cool seasons are especially desirable in some of our more northern states.

My attention was especially called to the importance of bud selection several years ago while buying my winter's supply of apples. I was examining the splendid crop of Jonathan apples in a neighbor's large commercial orchard. On most of the Jonathan trees the apples were large and well colored and the crop was heavy. However, a few trees bore apples of inferior size and color. Upon questioning the fruit grower as to the difference in the performance of the two types of Jonathan apple trees, he explained that the better apples came from trees supplied by a nurseryman who was very particular in selecting a good bud strain. The other trees were just the ordinary strain of Jonathan.