70 EXPERIMENTS IN BLUEBERRY CULTURE. 



his method, which may be regarded as a substitute for plunging, was ^ 



advantageous Tbecause it gave large aeration surfaces about the stones i 



in the interior of the earth ball and provided a place there for a large j 



development of roots which could not take place at the wall of the J 



pot. McXab's description of his method of repotting is as follows: 1 



Id shifting heaths I never reduce the old hall of earth more tlian hy rnl)liing i 

 the sides and bottom with the hand, so as to loosen the outside fibers a little. 

 I have often shifted heatlis twice, and even three times, in the course of the ! 

 spring and summer, with the greatest success. It is, however, quite unnecessary ' 

 to shift a heath until tlie young fibers have come througli the fresh earth given j 

 to it at its previous shifting, and begun to extend themselves round the inne)- 

 edge of the pot or tub : but as soon as this takes place, they may then be shifted 

 with advantage. This frequent shifting, however, is quite unnecessary, unless it 

 be to encourage a favorite specimen; for in all ordinary cases, particularly ! 

 when the plant is large, I consider one good shifting in two or three years quite j 

 sufficient. * * * , 



Besides the compost and draining which I have already mentioned, when I 

 begin to shift heaths I have always at hand a quantity of coarse, soft free- 

 stone, broken into pieces, from an inch to 4 or 5 inches in diameter. Of these ' 

 I always introduce a quantity among the fresh earth as it is put into the pot or \ 

 tub, round the old ball of earth about the plant, and press them well down 

 among fresh earth as it is put in. This I consider of great advantage to all 

 sorts of heaths, but more particularly so to those that may have been shifted 

 into a much larger pot or tub at once than what it had been grown in before, or ■ 

 in what I would call biennial or triennial shifting. These pieces of stone may 

 be put in as large as the opening will admit between the old ball and the edge 

 of the pot. In some of our largest tubs this opening is full 4 inches wide, and 

 where much earth is required to be put in the bottom over the draining before j 

 the plant is put in. a quantity of these stones should be mixed with the earth i 

 also. I likewise use occasionally large pieces of soft burnt bi-oken pots, put 

 among the earth in the same way as the stones; but I prefer stones when I can 

 procure them soft and free of iron. The quantity of stones which I introduce 

 along with a large-sized heath at shifting, will, in most cases, if broken down 

 into sand, and added to the sand previously in the soil, form about one-third. | 

 part of the whole mass. When stones are introduced among the earth in the I 

 way I have recommended, heaths will never suffer so much in the summer from 

 occasional neglect to water them as they would do if the stones were not intro- 

 duced, because these stones retain the moisture longer than the earth, and in 

 the winter they allow a freer circulation of any superabundant moisture which \ 

 may be given through the mass. 



The effect of the half shade used over the blueberries during the 

 summer of 1909 was to make the growth of the plants continuous , 

 instead of confining it to a brief period in the early part of the season, i 

 In a wild state the twigs of blueberry plants stop growing in early j 

 summer, the stoppage being indicated by the withering of the upper- 

 most leaf rudiment. The less vigorous twigs stop first, the more 

 vigorous ones next, and the shoots last. Stoppage of growth is has- 

 tened by hot dry weather and is deferred by cloudy humid weather. 

 In the latitude of Washington stoppage of ordinary twig growth in 

 wild plants of Vaccinium atrococcum begins in May and is usually 



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