Grafting.

I did a little grafting last spring, and as it was my first attempt, about ten per cent of the scions failed to grow.  Now shall I saw the stub off lower down and try again, or bud into one of the sprouts that have grown around the cut end?  The trees are pear and cherry.

You did very well as a beginner not to lose more than one-tenth.  Saw off below and graft again.  You might have budded into one of those shoots last July, and if you fail again, bud into the new shoots next summer.

Filling Holes in Trees.

I have a number of trees that, on account of poor pruning and improper care, are decaying in the center.  Many of them are hollow for a foot or more down the trunk.

Excavate all the decayed wood with a chisel or gouge or whatever cutting tool may work well and fill the cavity with Portland cement in such a way as to exclude moisture.  This will prolong the life and productiveness of the trees for many years if other conditions are favorable.

Deferring Bloom of Fruit Trees.

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.

Repairing Rabbit Injuries.

Your book says in Pruning young trees for the first time, about four main branches should be left and these cut back to 10 or 12 inches.  Now, where the rabbits have pruned back to 4 or 5 inches the very ones I wanted, what should be done?  Some say, cut these back to the stem, allowing new shoots to start from the base of branches so removed.