Chapter 10
OTHER TREES
Heartnut
The heartnut is a sport of the Japanese walnut (Juglans sieboldiana). Since its nut is heart-shaped, it has the name of "cordiformis" added to its species name. There are many of these sports, some of which have been propagated under the varietal names of Faust, Lancaster, Fodermaier, Wright, Walters, Canoka, Okay and Gellatly.
I think this is the most ornamental of all nut trees. In shape, it is similar to an apple tree, spreading out rather than growing tall, but its long, compound leaves give it a tropical appearance. During the autumn these leaves do not color any more than do those of the black walnut. The tree produces long racemes of red blossoms and its staminate blooms are catkins eight to ten inches long, which, when fully ripened, swish in the wind and release clouds of yellow pollen. The heartnut tree holds the interest of its owner closely during that time when the nuts resulting from the racemes of blossoms are steadily increasing in size. I have seen as many as sixteen nuts on one stem and doubtless, there sometimes are more. The owner of such a tree, at least if he is at all like me, will proudly exhibit it to all comers during the spring and summer seasons. And then, at harvest time, after the nuts have gradually changed from green to the dull yellow that indicates their maturity, he will have the satisfaction of shaking them down for drying and storage.
The heartnut kernel tastes much like that of the butternut and its internal structure is almost the same but the outside shell is smooth. Cultivated varieties usually crack easily and in such a way that the kernel is released in halves. From all this, it is easy to see that the heartnut is not only a beautiful tree but is definitely useful.
In my own work with heartnuts I have found that, although they are to be classed only as semi-hardy, there are a few varieties which are hardy enough for northern temperatures. Only testing will determine which ones can endure severe climates. In the spring of 1921, I planted a Lancaster heartnut grafted on a black walnut, but the weather was cold that season and it was killed down to the graft joint, where it threw out a sprout. This was weak and succulent by fall and the graft was entirely killed back that winter. I bought twelve more Lancaster heartnuts a year later. They were interspersed in the orchard among some black walnuts. Although a few survived the first winter, none ever lived to come into bearing. From time to time, I also experimented with seedlings sent to me by Professor James A. Neilson of Vineland, Ontario, who was interested in having them tested in this latitude. These, too, were always unsuccessful.
I had my first success with several unnamed varieties of heartnuts I purchased in 1933 from J. U. Gellatly of British Columbia. These were grafted on black walnut stocks of considerable size. To insure their surviving the first winter, I built wooden shelters which completely enclosed them, filling these shelters with forest leaves and protecting them against mice with screen covers. No doubt this was a decided help; at least all of these heartnuts lived for many years until the invasion of the butternut curculio and the damage done by the yellow bellied sap sucker bird caused me the loss of all except one variety, the Gellatly. This variety I have perpetuated by re-grafting on other black walnut stocks and by spraying and covering the limbs with screen to prevent the sap sucker from working on it, still have it in the nursery and at my home in St. Paul where a young tree on the boulevard bears each year.
I have found that heartnuts are difficult to propagate, the number of successful grafts I have made being far below that of black walnuts on black walnut stocks. The reason for this is not well understood any more than is the fact, in my experience, that the Stabler walnut will graft readily and the Ten Eyck persistently refuses to. A good feature that these grafted trees do have, however, is their early productiveness. I have seen them set nuts the second year after grafting and this has also occurred in trees I have sold to others.
When a nut of J. sieboldiana cordiformis is planted, it does not reliably reproduce itself in true type, sometimes reverting to that of the ordinary Japanese walnut, which looks more like a butternut and has a rather rough shell as distinguished from the smooth shell of the heartnut. In hulling my heartnut crop for 1940, I noticed many deformed nuts.