Occasionally, it may assume some qualities of the
original top. Such cooperation is necessary if either is to survive.
First of all, the grafted scions must accept the vital quality of
climatic hardiness, a powerful factor developed through ages spent in a
certain climate. To hasten the acclimatization of a tender variety, I
cut scionwood from such unions early in the winter, storing it until
spring. When these scions are grafted on new root systems, I find that
they are much more readily accepted than the first grafts were. The
following season, I allow the grafts of this later union to go through
their first winter of exposure. Early each spring I continue to cut
scions from the most recent unions and graft them to new root systems,
so hastening and setting the factor of hardiness through frequent
asexual propagation.
Because my observations of the effects of scion on root and vice versa,
have not extended over a sufficient period of time, I think it is
possible that the changes I have seen may be only transient. In any
case, I do know that the phenomenon occurs, for I have seen many
examples of it.
One instance in which the stock was apparently affecting the scions,
occurred in the case of several varieties of black walnuts which had
been grafted on wild butternut stock over a period of sixteen years.
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