36 EXPERIMENTS IX BLUEBERRY CULTURE. 



either about the margin of the bog or on hummocks. In both these 

 situations most of the roots of the bhieberry bushes stand above the 

 summer level of the water. ^Vlien a bog has l)een built up bv the 

 growth of vegetation and the accumulation of the debris until the 

 surface is above the summer water level, the swamp blueberry' will 

 occur ofenerallv over the bog. 



An examination of blueberry plants occurring on hummocks and 

 bog margins has shown that such roots as extend beneath the per- 

 manent summer water level bear few feeding rootlets or none at all. 



In one experiment it was attempted to grow blueberry seedlings 

 in water cultures containing various dissolved nutrients. It was 

 found that the roots made no new gi'owth. that the new leaves were 

 few and small, and that the general health of the plants was not 

 good, whatever the character of the nutrient substances in the solu- 

 tions. It was frequently observed also in the various soil cultures, 

 particularly those in undrained glass pots, that the continued satu- 

 ration of the soil with water reduced the root growth and enfeebled 

 the Avhole plant. Continued excessive watering of potted blueberry 

 plants Avas always found injurious. 



The observations just recorded must not be understood to mean 

 that submergence of the roots is always injurious to the swamp blue- 

 berry. In winter and early spring the water level of bogs containing 

 blueberries often remains high enough for several months to com- 

 IDletely submerge the Avhole root system of the plants. On the lower 

 end of the AVankinco cranberry bog near Wareham, Mass., are some 

 native bushes of the swamp blueberry, the roots of which have been 

 submerged in 3 feet of water from December to ^lay each year for 

 about twenty years. These bushes when observed in September. 1909, 

 gave every evidence of vigor. Their twig growth was of gcK)d length 

 and thickness, their foliage was dense and of a healthy color, their 

 flowering buds for the next vear were fairlv numerous, and the bushes 

 were said to be as productive of fruit as neighboring bushes on higher 

 ground. 



It would appear from these facts that, while submergence during 

 the dormant period is not injurious to the swamp blueberry, its roots 

 during their actively growing period must be kept above the water 

 level so as to be well aerated. 



(10) .^XRATION CONDITIONS S.\TISFACTORY FOB THE SWAMP BLUEBKRBY ARE PREVA- 

 LENT IN SANDY SOILS. 



The experiment cited above on this page showed that blueberry 

 seedlings having their roots suspended in nutrient solutions failed to 

 make a normal growth even though the solutions were suitably acidu- 

 lated. This failure was ascribed to lack of aeration. In another 

 experiment, described on pages 28 and 29, it was shown that a similar 

 nutrient solution when used to water a blueberry plant potted in sand 

 produced a normal growth of both roots and stems. The sand fur- 



