1947 Observations of Winter Injury 
Further studies made in Kentucky, Illnois, Indiana, Ohio, West Virginia, Virginia, North Carolina 
and Georgia during Summer 1947 confirms to a great degree that most injury from cold occurs in late 
November through December. Most case studies further confirmed the fact that incomplete dormancy 
of trees was largely responsible for the injury. 
Trees growing under continuous and late cultivation which went into winter with inmature wood 
were most severely injured. Considerable damage has always been done to peach trees by cultivating 
them until late in the season - some growers believe this to be necessary in years of heavy crops to 
secure best sizes and highest yield, but the cultivation should be stopped early to allow time enough to 
mature the wood before hard freezing occurs. 
STUDIES OF SOIL CONDITIONS CONTRIBUTED SOME INTERESTING FACTORS: 
A. Trees growing on poorly drained soil were more likely to be injured than those on well drained 
land. 
B. Where cover crops and mulches were used, injury was greatly reduced. 
C. Root killing on poorly drained soil occured in a great many observations made without observ- 
able injury to limbs or buds of the tree. In such cases, the tree often bloomed in the spring 
and set fruit only to die in mid-summer. 
D. Trees growing in poorly drained soil which were subject to high winds suffered more than any 
other conditions found. 
Age of tree showed interesting contrasts in various localities. Trees 2 to 5 years of age showed 
more definite early winter injury than older trees, pointing to the fact that cultivation does not stim- 
ulate the older trees to the degree found in younger trees. Where trees were injured in the 6 to 9 year 
ages, cross section cuts invariably disclosed frost injury at an earlier age, showing suscesptibility to cold 
in that particular location. 
Pruning studies show definitely that early pruning may be a hazard where winter injury occurred. 
Early season pruning was accompanied by injury in direct ratio to amount and severity of pruning 
done. Age of tree here determined amount injury, trees under 4 years suffering most. 
Insects and diseases which caused defoliation of the tree where observed, showed a marked increase 
in winter injury. Likewise spray injury to foliage weakened tree resistance materially and caused 
an accentuated injury. 
Variety studies were made covering hardiness and some found hardier than others, but due to the 
fact that relative hardiness varies from season to season, no concrete examples will be given here. Again, 
there are various types of hardiness, such as hardiness of wood, leaf bud, fruit bud, etc. A variety may 
be hardy in one respect and tender in another. Hardiness of root stocks may be a factor for future 
consideration in this respect. 
Studies concerning fertilizing showed a wide range material used and many methods of application 
and while of paramount importance with regard to winter injury, the subject cannot be treated here, 
except to state that fall application of fertilizer has proved beneficial in tending to prevent late winter 
injury and to stimulate fruit buds, making them hardier during blooming period and resulting in more 
uniform crops. 
Moisture and fertilizer are the balance wheels of successful operation. Where extreme dry condi- 
tions of early or midsummer are followed by too much moisture in late season the results will always 
be a restimulation of the sap flow and a late dormancy can be expected. This late dormancy will in most 
cases carry over into the hard freezing temperatures with disastrous results, particularly in non-bearing 
trees and those under six years of age, where culture programs are carried on to force maximum growth. 
Many young orchards fail to produce normal crops or the trees die early from unexplained causes, when 
in reality the hidden winter injury of the first or second year after planting is responsible. 
The question now arises - can winter injury be prevented? A few recommended practices may be 
considered to avoid winter injury: 
1. Plant on well drained soil or soil capable of drainage where low spots occur. 
B. Plant only on best possible frost free location and on deep soil of moderate fertility. Air 
drainage is equally important. 
2. Prune young trees after severe winter temperatures are over. Where early pruning is practiced, 
confine cutting to taking out interfering wood and water sprouts. 
3. Use only mild sprays in order that foliage may be in best condition to mature the wood tissues 
properly. : 
4. Avoid overloading trees with fruit by thinning properly. An overerop of fruit tends to weaken 
the tree generally. 
5. Use moderate application of balancing fertilizers, made in fall and again in spring to keep trees 
growing well, but not over vegetative in order that wood growth may mature properly. 
By following the above few simple rules, it is possible to have fruit trees go into winter tempera- 
tures in good physical condition to withstand average low winter cold without damage to tree or buds 
and have consistent crops of fruit during.the life of your trees. 
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