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.