516 



BLUEBERRY 



BLUEBERRY 



Although some species of Vaccinium, such as the 

 common low-bush blueberry, V . pcnnsylvanicum, grow 

 and fruit abundantly in sandy uplands that are sub- 

 ject to drought, the swamp blueberry grows best in 

 soils naturally or artificially supplied with adequate 

 moisture. 



These then are the three fundamental requirements of 

 successful blueberry culture: (1) An acid soil, especially 

 one composed of peat and sand; (2) good drainage and 

 thorough aeration of the surface soil; and (3) perma- 

 nent but moderate soil-moisture. Under such conditions, 

 the beneficial root-fungus which is believed to be essen- 

 tial to the nutrition of the plant need give the cultivator 

 no concern, for it will propagate itself spontaneously 

 and adequately, without any necessity of soil or plant 

 inoculation. 



Propagation. 



Blueberry plantations may be formed by the trans- 

 planting of unselected wild bushes or by the growing 

 of seedlings, but such a course is not the best. Seedling 

 plants, even from the largest-berried parents, produce 

 small berries oftener than large ones. Until nurserymen 

 are prepared to furnish plants asexually propagated 

 from superior stocks, the cultivator should begin by 

 the transplanting of the best wild bushes, selected when 

 in fruit for the size, color, flavor, and earliness of the 

 berry, and the vigor and productiveness of the bush. 

 These he should propagate by layering and by cuttings 

 until his plantation is completed. By means of a com- 

 bination of these two methods, a valuable old plant 

 can be multiplied by several hundred at one propa- 

 gation, the fruit of the progeny retaining all the 

 characteristics of the parent. 



Large berries cost less to pick than small ones and 

 bring a higher price. A berry J of on inch in diame- 

 ter has already been produced under cultivation and 

 others of still larger size are to be expected. 



While grafting and especially budding are useful 

 in experimental work, neither method is suitable for 

 commercial plantations because blueberry bushes are 

 continually sending up new and undesirable shoots 

 from the stock. The best season for budding is from 

 the middle of July to the end of August. The budded 

 plants should be protected from direct sunlight, and 

 special care should be taken that the raffia wrapping 

 does not become wet for the first three weeks. 



The easiest way to propagate the swamp blueberry is 

 by a special process of layering known as "stumping." 

 In early spring, preferably before the buds have begun 

 to push, all the stems of the plant, or as many as it is 

 desired to sacrifice for propagation, are cut off close to 

 the surface of the ground. The stumps are then covered 

 to the depth of 2 inches with a mixture of about four 

 parts of clean sand and one of sifted peat. The sand- 

 bed must not be allowed to become dry, except at the 

 very surface. The new growth from the stumps, which 

 without the sand would consist of stems merely, is 

 transformed in working its way through the sand into 

 scaly, erect or nearly erect rpotstocks which on reach- 

 ing the surface continue their development into leafy 

 shoots. Although roots are formed only sparingly on 

 the covered bases of stems, they develop quickly and 

 abundantly on these artificially produced rootstocks. 

 By the end of autumn the shoots are well rooted at the 

 base. They should remain in place in the sand-bed 

 through the winter, exposed to freezing temperatures. 

 Early in the following spring, before the buds have 

 begun to push, each rooted shoot js carefully severed 

 from the stump. The upper portion of the shoot is 

 discarded, .the cut being made at such a point as to 

 leave on the basal portion about three buds above the 

 former level of the sand-bed. The rooted shoots are 

 potted in clean 3-inch porous pots in a soil consisting 

 of two parts of rotted upland peat to one of sand and 

 one of clean broken crocks. They are then plunged in 



sand in a shaded coldframe or greenhouse, with abun- 

 dant' light but no direct sunlight. For the first twc 

 months the temperature should be kept below 65 F. 

 When subjected to high temperatures, the newly cut 

 shoots arc liable to die and rot from the base upward. 

 Watering should be infrequent, only sufficient to keep 

 the soil moist but well aerated. The frame should re- 

 ceive ventilation but not enough to cause the new twigs 

 to droop. They are very susceptible to over-ventilation 

 and overheating just before they complete their pri- 

 mary growth. After the new twigs have stopped growing 

 and their wood becomes hard, new root-growth takes 

 place. Then secondary twig-growth follows. Not until 

 this has occurred is the life of the plant assured. Those 

 plants that make sufficient growth to require repotting 

 during the first summer should be transferred to clean 



Ci of 2 inches larger diameter in a standard blue- 

 y soil mixture. 



A very successful potting mixture, or nursery-bed 

 mixture, for blueberry plants consists of one part of 

 clean or washed sand, nine parts of rotted upland peat, 

 either chopped or rubbed through a sieve, and three 

 parts of clean broken crocks. 

 No loam and especially no 

 lime should be used. Ma- 

 nure is not necessary, and 

 in the present state of our 

 knowledge may be re- 

 garded as dangerous, al- 

 though in small amounts 

 it serves to stimulate the 

 plants, at least temporarily. 

 The danger from manure 

 apparently lies in its ten- 

 dency to produce an alka- 

 line condition in the soil. 



The use of crocks in the 

 potting mixture is based on 

 the fact that the rootlets 

 seek them and form around 

 them the same mats that 

 they form at the wall of 

 the pot, thus increasing 

 the effective root-surface 

 and the vigor of growth. 



The peat most success- 

 fully used for potting blue- 

 berry plants is an upland 

 peat procured in kalmia, or 

 laurel, thickets. In a sandy 

 soil in which the leaves of 

 these bushes and of the oak 

 trees with which they usually grow have accumulated 

 and rotted for many years untouched by fire, a mass 

 of rich leaf-peat is formed, interlaced by the super- 

 ficial rootlets of the oak and laurel into tough mata 

 or turfs, commonly 2 to 4 inches in thickness. These 

 turfs, ripped from the soil and rotted from two to six 

 months in a moist but well aerated stack, make an 

 ideal blueberry peat. A good substitute is found in 

 similar turfs formed in sandy oak woods having an 

 underbrush of other ericaceous plants than laurel. Oak 

 leaves raked, stacked, and rotted for about eighteen 

 months without lime or manure are also good. The 

 leaves of some trees, such as maples, rot so rapidly 

 that within a year they may have passed from the 

 acid condition necessary for the formation of good 

 peat to the alkaline stage of decomposition, which is 

 fatal to blueberry plants. Even oak leaves rotted for 

 several years become alkaline if they are protected from 

 the addition of new leaves bearing fresh charges of 

 acidity. 



By ordinary methods, cuttings of the swamp blueberry 

 have been rooted only in occasional instances. Two ^uc- 

 cessful methods, however, have been especially devised 

 for these plants. The most novel of these but the one 



586. Swamp Blueberry. A 

 cluster of berries on a budded 

 greenhouse plant. ( X 1 A). 



