Literature Cited
1. Barton, Lela V.—Seedling Production in Carya ovata, Juglans cinerea, and Juglans nigra. Cont. Boyce Thompson Inst. 8:1-5. 1936
2. Becker, Gilbert—Notes from Southwestern Michigan. Rept. North. Nut Grow. Assoc. 28:135. 1937
3. Bernath, Stephen—Propagating Nut Trees under Glass. Rept. North. Nut Grow. Assoc. 37:90. 1946
4. Chase, Spencer B.—Black Walnut Nursery Studies. Rept. North. Nut Grow. Assoc. 37:40-41. 1946
5. Chase, Spencer B.—Eastern Black Walnut Germination and Seedbed Studies. Jour. For. 45:661-668. 1947
6. Chase, Spencer B.—Budding and Grafting Eastern Black Walnut. Proc. Amer. Soc. Hort. Sci. 38:175-180. 1947
7. Gellatly, J. U.—Notes on Nuts and New Combinations of Old Principles. Rept. North. Nut Grow. Assoc. 29:115-120. 1938
8. Hardy, Max B.—The Propagation of Chinese Chestnuts. Rept. North. Nut Grow. Assoc. 40:121-126. 1949
9. Joley, Lloyd E.—Personal Correspondence. July, 1951
10. Lounsberry, C. C.—Bench Grafting of Black Walnuts. Rept. North. Nut Grow. Assoc. 28:60. 1937
11 MacDaniels, L. H.—Some Experiences in Nut Tree Grafting at Ithaca, New York. Rept. North. Nut Grow. Assoc. 28:52. 1937
12. McKay, J. W.—Results of a Chinese Chestnut Rootstock Experiment. Rept. North. Nut Grow. Assoc. 38:83-84. 1947
13. Morris, R. T.—Top Working Hickories—Rept. North. Nut Grow. Assoc. 11:105. 1920
14. Morris, R. T.—Nut Growing. 1931. Macmillan, New York
15. O'Rourke, F. L.—Unpublished data. 1940-1945
16. Painter, John H.—Personal Correspondence. July-August, 1951
17. Reed, C. A.—Nut-Tree Propagation. U.S. Dept. of Agr. Farmers' Bul. 1501. 1926
18. Reed, C. A.—Seedling Chestnut Trees versus Grafted Varieties. Rept. North. Nut Grow. Assoc. 32:79. 1941
19. Shelton, E. M.—Glauber's Salt for Humidity Control in Scion Storage. Rept. North. Nut Grow. Assoc. 28:70-71 1937
20. Shelton, E. J.—A Laboratory Experience in Testing Wax Mixtures for Use in Plant Propagation. Rept. North. Nut Grow. Assoc. 28:72-75. 1937
21. Shessler, Sylvester—Grafting Walnuts in Ohio. Rept. North. Nut Grow. Assoc. 39:145. 1948
22. Sitton, B. G.—Vegetative Propagation of the Black Walnut. Mich. Agr. Expt. Sta. Tech. Bul. 119. 1931
23. Sitton, B. G.—Pecan Grafting Methods and Waxes. U. S. Dept. Agr. Circ. 545. 1940
24. Slate, George L.—Grafting Walnuts in the Greenhouse. Rept. North Nut Grow. Assoc. 39:146-147. 1948
25. Smith, Gilbert L.—Our Experience with Rootstocks. Rept. North Nut Grow. Assoc. 40:62-64. 1949
26. Stoke, H. F.—Nut Nursery Notes—Rept. North. Nut Grow. Assoc. 34:96. 1943
27. Stoke, H. G.—Grafting Methods Adapted to Nut Trees. Rept. North. Nut Grow. Assoc. 37:99-102. 1946
28. Weschcke, Carl—The Importance of Stock and Scion Relationship in Hickory and Walnut. Rept. North. Nut Grow. Assoc. 39:190-195. 1948
29. Wilkinson, J. F—Preparation of Stocks for Propagation. Rept. North. Nut Grow. Assoc. 28:65-66. 1937
30. Zarger, Thomas G.—Nut-testing, Propagation, and Planting Experience of 90 Black Walnut Selections. Rept. Nut Grow. Assoc. 36:23-30. 1945
Nut Rootstock Material in Western Michigan
Harry P. Burgart, Union City, Michigan
It is only natural that those who propagate by budding and grafting are always hoping to find a rootstock that will accept their scions with the highest percentage of takes and impart vigorous growth to the scion variety. Sometimes in our eagerness to adopt a new rootstock we are likely to neglect a vital point, namely—Future Performance of the root-top combination we are about to use.
It would take years of observation in a test planting to prove whether or not a new rootstock material is safe to use. A rootstock can affect the tree it supports in various ways. Sometimes the rootstock will force to the top too much growth, which is likely to bring about unfruitfulness. In other cases, the rootstock may cause a dwarfing habit in the future tree, with the resulting top being a scant producer of nuts. Then there is the combination where rootstock and top vary too much in their growth rate, thus making an unsightly tree. The ideal rootstock is one that attains a diameter nearly equal to the diameter of its partner, and is capable of producing a moderate amount of top growth, together with the production of heavy crops of nuts. Such a rootstock should also accept buds or grafts readily, and be compatible with the scion throughout the life of the tree.
My first experience with rootstocks for grafting came about in 1926 when I was working at the J. F. Jones Nursery then at Lancaster, Pennsylvania. Mr. Jones used both bitternut and pecan seedling stocks for grafting shagbark hickories. Pecans and hicans were also grafted on hardy northern pecan seedlings, and Japanese walnut stocks were used for butternuts and heartnuts. Black and Persian walnut scions were set on eastern black walnut seedlings.
When I returned to Michigan I brought back enough of Mr. Jones' trees for a small test planting here at Union City. These trees were planted in a heavy quack grass sod and some were lost, but those surviving show good compatibility between the top and root.
In the intervening years I have made but slight changes in the rootstock material used in my own nursery. I do not approve of the performance of our butternut varieties on the Japanese walnut root, as it results in a weak and dwarfed tree. The use of butternut rootstocks is also unsatisfactory, for they tend to produce trees of low vitality that in a few years fall victim to blight and then perish. I tried our Michigan black walnut seedlings as a rootstock and found that they are very much better rootstock material. The growth at the union is about equal. Top growth is good, and the butternut tops bear early and heavily, with no signs of blight during the ten years I have had them under test.
After years of test I have decided to use the northern pecan seedlings as rootstocks for my shagbarks, pecans, and hicans because they are a fast growing stock tree. They accept the grafts readily, and make good unions more quickly than the bitternut stocks I have tried. Mr. Wilkinson, from whom I obtain my seed, has never failed to send me seed with good viability, just about every seed germinating. The northern pecan seedlings have shown no winter injury here in Southern Michigan during the 20 years I have watched them growing.
An example of the superiority of the black walnut over the Persian walnut as a rootstock is a seedling of the variety Wiltz Mayette growing near a Broadview grafted on black walnut. Both trees are the same age, but the Broadview on black walnut is just about twice the size of its own-rooted neighbor.
Hudson Valley Experience with Nut Tree Understocks
Gilbert L. Smith, Millerton, N. Y.
This report is not based on any planned or well conducted experiments, but is based simply on our observations of results of our grafting work over the years since 1934.
Our first work was with hickories, so I will start with them.
Our first year's grafting was done in a plot of practically pure pignut stocks. This was the seven leaflet pignut, which I believe to be Carya glabra. I have never been sure of the identification of the two species of pignuts. We secured a fairly good percentage of living grafts, which grew well the first summer. The next spring all of the grafts failed to leaf out and later were found to be dead. A few grafts which were put on bitternut stocks (Carya cordiformis) grew well, and are still growing well after more than fifteen years. Several different varieties of shagbark hickory scions were used in this grafting.
The second year, we again grafted as many or more stocks in this same area. The results were exactly the same, except that we used some scions of Davis and Fox. (These varieties were brought to light through the contests of the previous winter). The grafts of Davis grew on pignut stocks, are still alive and doing fairly well. They have been bearing for several years, although the squirrels have stolen all of the nuts. Grafts of all other varieties which were on the pignut stocks died the next spring. One graft of Fox on mockernut lived and has continued to grow fairly well. That same year we started our test orchard of shagbark stocks (Carya ovata) in a different area. Grafts on these stocks have grown very well.
I believe that for some reason grafts of shagbark on pignut stocks cannot stand cold weather. Certainly, incompatibility is very marked.
Our experience with hickory stocks to date is as follows:
Pignut (Carya glabra or possibly Carya ovalis). This species is worthless as a stock for shagbark, shellbark, and hybrids of these species. If nut growers have some pignut stocks growing where they especially wish to have some good hickory trees, they can graft them to Davis. We have also heard that Brooks will grow on pignut stocks.
Mockernut (Carya alba). This species is also nearly worthless as a stock for shagbark, shell bark, and hybrids, although many more varieties will live on it than will on pignut stocks.
Shagbark (Carya ovata). This species makes the most dependable stock of any we have tried so far, for shagbark, shell bark, and the hybrids. Its greatest drawback is the long time it takes to grow seedlings to a size large enough to graft.
Shellbark (Carya laciniosa). We have never had an opportunity to use this species as a stock. I think that it would make a good one and possibly be faster growing than shagbark.
Bitternut (Carya cordiformis). We have found that this species makes a very satisfactory stock for shagbark and hybrid grafts. We have not tried shellbark on it, except Berger which grows well on it. Seedlings of this species are much faster growing than are shagbark seedlings, and thus are large enough to graft sooner. We have grafts growing on bitternut stocks since 1935, they are growing and producing well. We consider this species as good or nearly as good as shagbark as a stock.
We have received contrary reports from farther south. These may be due to stock being blamed for something they did not cause or it may be that bitternut stocks grown from seed of more southern origin may not be as good as our northern stock.[18]
Pecan (Carya pecan). Our experience with this species as a stock is very limited and has been confined to grafts of only one variety of shagbark (Wilcox). Results were very disappointing, but we have been told by others that it makes a good stock. It is much faster growing than is shagbark.