In 1921, I began ordering grafted black walnut trees, as well as grafted hickory trees from J. F. Jones, who had the largest and best known of the nurseries handling northern nut trees.  Some of these grafted trees were also planted at my home in St. Paul, using the two locations as checks against each other.  The site in St. Paul eventually proved unsatisfactory because of the gravelly soil and because the trees were too crowded.  The varieties of black walnuts I first experimented with were the Thomas, Ohio, Stabler and Ten Eyck, which were planted by hundreds year after year.  If I had not worked on this large scale there would be no reason for me to write about it today as the mortality of these black walnuts was so high that probably none would have lived to induce in me the ambition necessary to support a plan involving lengthy, systematic experimentation.  Some of these early trees survive today, however, and although few in number, they have shown me that the experiment was a worthy one since it laid the foundation for results which came later.  In fact, I feel that both the time and money I spent during that initial era of learning were investments in which valuable dividends of knowledge and development are still being paid.

In grafting black walnuts on butternut trees, I very foolishly attempted to work over a tree more than a foot in diameter and I did not succeed in getting a single graft to grow on it.  Other younger trees, from three to six inches in diameter, I successfully grafted.  Some of these are still living but clearly show the incompatibility of the two species when black walnut is grafted on butternut.  The opposite combination of butternut on black walnut is very successful and produces nuts earlier and in greater abundance than butternut does when grafted on its own species.

The expense of buying trees by hundreds was so great that after a year I decided that I could very easily plant black walnuts to obtain the young trees needed as understocks.  When they had grown large enough, I would graft them over myself.  I wrote to my friend in St. Peter, Mr. E. E. Miller, and he told me where I could obtain walnuts by the bushel.  Soon I was making trips to the countryside around St. Peter buying walnuts from the farmers there.  I planted about five bushels of these at the River Falls farm and the rest, another two bushels, at St. Paul.  Soon I had several thousand young walnut trees which all proved hardy to the winters.

When pruning the black walnut trees purchased from Mr. Jones for transplanting, I saved the tops and grafted them to the young trees with a fair degree of success.  In a few years, I was using my own trees to fill up spaces left vacant by the mortality of the Pennsylvania-grown trees.  I did not neglect seeding to provide stocks of the Eastern black walnut also, which is almost a different species from the local black walnut, but these seedling trees proved to be tender toward our winters and only a few survived.