Reed(16) summarized the rootstock studies at Beltsville, Maryland, by stating that pecans were best on pecan seedlings and that shagbarks were successful on either shagbark or pecan rootstocks. He reported a lack of congeniality between shagbark and bitternut hickory. Smith(21), however, found that pecan stocks were unsuccessful for shagbarks as few scions lived and growth of those which survived was poor. He also reported that bitternut was practically as good as shagbark for shagbark varieties. He stated that pignut was absolutely useless as a stock for shagbark. Weschcke(24) reported that shagbark varieties grew well on bitternut but also indicated that a slow growing variety would be stimulated in growth by working on pecan stocks which are more vigorous in growth than the other hickories. Dunstan(8) reported that pecan provides a perfectly satisfactory rootstock for shagbark, shagbark hybrid, and hican varieties. A number of varieties have been tested over a period of several years with favorable results as shown by lasting unions and better than average yields.
The Fairbanks hybrid has often been used as an intermediate stock between bitternut and some shagbark varieties and Last(10) has stated that the variety Rockville is useful for interstock purposes on account of its exceptional vigor.
Nursery Problems
Hickories and pecans have long tap-roots with few branches and hence do not transplant well. Some few have grown the seedlings for one year in beds underlain with wire screen netting or have undercut the seedlings to promote branching of the roots. The stocks must grow two years from seed to attain a diameter permitting of patch budding and must remain one or two years more to allow the scion to form a tree. The resulting plant is large in both root and stem and requires careful handling in digging, shipping, and planting in the permanent location. The vicissitudes which befall the production of the northern hickories are often so great as to discourage nurserymen who otherwise would grow them. This is an unfortunate fact but a real one, as the would-be purchaser often learns when he attempts to buy named varieties of hickories. The situation with the pecan is much better, due perhaps to the greater demand for such trees but also to the greater ease of propagation in general nursery practice.
Conclusions
Good varieties of hickories bear good nuts and more people should plant good trees which should be produced by nurseries with well-branched fibrous root systems so that they will transplant easily. Research is needed to determine practical methods of propagation which will permit of inexpensive quantity production of superior named varieties of shagbark and shagbark hybrid hickories.
Literature Cited
1. Barton, Lela V. Seedling production in Carya ovata, Juglans cinerea, and Juglans nigra. Cont. Boyce Thompson Institute 8:1-5. 1936.
2. Becker, Gilbert. Notes from Southwestern Michigan. Rpt. North.
Nut Grow. Assoc. 28:135-136. 1937.
3. Benton, Wm. A. Report on propagation of nut trees. Rpt. North.
Nut Grow. Assoc. 29:90-92. 1938.