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  38 TMrty-Sixth Amzual Report _
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    type failed to produce any fruit, quite in accordance with their -
  ~ reputation of being tender in bud.
~ n=.t·;»;7   if .
  Plums. The weather conditions which apparently were
it   i responsible for such wide variations in the behavior of peaches,
    resulted in similar variations in the amount of injury to plums.
  _`_i     Some of the native species, supposedly very hardy, suffered
  Q most, while others often found more tender in northern re-
    gions were practically unharmed. The injury that occurred
  in peaches and in Prunus domestica. consisted in the killing of
    · the essential organs of the flower and was easily recognized
    by the blackened pistils. Such injury did not affect the other ·
  parts of the flower or prevent its opening, while the injury
  to the Japanese plums and many native species and hybrids
   lg consisted in killing the entire flower bud and, in some cases, the
 I  __ leaf bud as well, occasioning the later development of adventi-
  tious buds. The former results in little or no impairment of
  tree vigor, while the latter caused the death of the spurs and
  V smaller branches, so that the trees did not come into leaf until
  adventitious buds sprang up along the main branches, thus
 ~  . producing a marked check upon the vitality of the tree.
    ' The problem of hardiness differs in Kentucky from that
  · in the northern states in that here trees rarely suffer from
  winter killing from low temperatures, but rather from freezes
  V tafter the buds have swollen in late winter. The records show
  that many of the varieties which originated in Iowa, the Da-
  kotas and other parts of the cold Northwest, usually regarded
Li .   as among the hardiest, were severaly injured under the condi-
  tions described above, while other varieties less hardy to
  absolute cold in northern regions, received little injury. The
  requirement for hardiness in this state, therefore, seems to be
  V met thru prolonged dormancy rather than thru resistance to
  >  , low temperatures during the winter. The early blooming
  varieties of Japanese plums, Japanese hybrids and native spe-
  cies are not as reliable as those which bloom later or which
  _ have a longer blooming season. In the 1922 season the varie-
  ties of P. domestma named above were decidedly superior to
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