TAMING THE WILD BLUEBERRY 121 



This and similar acid mixtures have been used with success on 

 bhieberry plants in both pot and field experiments, with no evidence 

 thus far of cumulative injurious effects. However, as no fertilizer 

 is required to make the swamp blueberry fruit abundantly and 

 continuously in suitable peat and sand soils properly handled, 

 the use of fertilizers in commercial plantations is not at present 

 advocated. 



The swamp blueberry does not require a yearly pruning. When 

 one of the stems of a bush becomes unproductive from injury or old 

 age it should, of course, be cut out. If a large part of a bush needs 

 removal it is better to cut all the stems to the ground and let the 

 plant send up new shoots, all of the same age, to form a wholly new 

 and symmetrical top. 



I Yield and Profits. 



By proper manipulation in the greenhouse, seedling blueberry 

 plants can often be made to ripen a few berries in less than a year, 

 but they do not come into commercial bearing in field plantations 

 until they are 3 to 4 years old, when the plants are 1 to 3 feet high. 

 They then increase slowly to full size and full bearing. Wild 

 bushes of the swamp blueberry live to great age, often 50 to 100 

 years, still bearing heavily, and they often attain a height of 6 to 8 

 feet when growing in full sunlight; still more when shaded. Indi- 

 vidual stems may remain productive for 10 to 25 years. When 

 dead they are replaced by new and vigorous shoots from the root. 



The field plantings resulting from the recent experiments in blue- 

 berry culture are too young to show the mature yield. Fortunately 

 however, there is, near Elkhart, Ind., a small blueberry planting of 

 mature age. The returns from this plantation set forward our 

 knowledge of yields by at least a decade. The plantation is about 

 2^ acres in extent. It was started in 1889 in a natural blueberry 

 bog, which was first drained and then set with unselected wild-blue- 

 berry bushes. The plantation was profitable from the first, but 

 exact records of yield and receipts are available only for the years 

 1910 to 1915, when the plantation was 21 to 26 years old. The 

 dataare shown in Table I. 



