Deferring Bloom Of Fruit Trees

Categories: Fruit Growing

Have any experiments ever been carried on definitely to decide what

causes early blossoming of fruit trees? For instance, have adjacent

trees of the same variety been treated definitely by putting a heavy

mulch around one to hold the cold temperature late in the spring,

leaving the other tree unmulched so the roots could warm up?



It has been definitely determined by the experiments of Professor

Whidden of the Missouri Experiment Station that the swelling of the buds

and starting of the foliage of fruit trees is due to the action of heat

upon the aerial parts of the trees; that is, growth is not caused by

increasing the temperature of the ground and cannot be retarded by

cooling the ground. Experiments with the use of snow and ice under trees

by which the ground has been kept at a low temperature have not

prevented the activity of the tree. The only way known to retard

activity is to spray the tree with whitewash so that the white color may

reflect the heat and prevent the absorption of it by the bark, which is

usually of a dark color and therefore suited to heat absorption.

Retarding of growth is possible in this way for a period of six to ten

days, which, of course, in some cases might be of value, but the

lengthened dormancy is probably too small to constitute it of general

value. In whitewashing, to determine what advantage there is in it in

retarding growth, the tree should be thoroughly sprayed with whitewash

so as to cover all the wood some time before the buds swell. In fact, it

is to prevent the early swelling of the buds that the whitewashing is

resorted to. It is better to make the application, therefore, a little

too early than too late. A specific date cannot be given for it that

would be right in all localities.