96 HORTICULTURAL MANUAL. 



Over the comparatively level surface of the whole Missis- 

 sippi valley the small fruits, such as strawberry, raspberry, 

 and blackberry, are materially benefited by tree-shelter on 

 the south and west to lessen evaporation from the drying 

 winds prevalent, during the summer from these points. 

 With such protection less trouble is experienced from 

 fungus attacks of leaf and bark and more even and perfect 

 development of the fruit is secured. 



100. Retarding the Blossoming Period. The belief is 

 quite general that quite heavy mulching of the roots of 

 orchard trees when the ground is deeply frozen will retard 

 the blossoming period. Eepeated trials at the experiment 

 stations and by private orchardists have demonstrated the 

 fact that this belief has no foundation. 



The flowers and leafage are started in spring by the 

 temperature of the air. If we draw a branch of the grape 

 or other climber through a hole into a greenhouse or warm 

 room it will soon develop blossoms and leaves when its 

 roots are encased in frozen earth and the temperature is 

 that of winter outside. For this reason the retention of 

 frost in the soil will not retard the period of flowering a 

 single hour. This is true also of shrubs, vines, and all 

 ligneous plants with tops exposed to the air. But straw- 

 berry-plants, grapes, climbing roses, and, indeed, any 

 growth laid down and covered with earth or litter, will 

 be retarded in blossoming several days. 



The principle involved is that the bursting-time of 

 flowers and leaves depends on local stores of nutriment 

 stored in the cell-structure, and to some extent it is inde- 

 pendent of root action. But the roots usually are not 

 frozen at the season of blossoming even when encased in 

 frozen ground. Moisture really ascends to the top when 

 the air-temperature is warm enough to start top-growth; 

 that is, enough moisture to expand the flowers and start 



