PLUM 



PLUM 



1377 



much more spreading and strong supporting system of 

 roots. This has come to be generally recognized, 

 and seedlings are now usually the rule. This is all- 

 important in California, for there the roots of all plants 

 must necessarily go deep for their moisture and nour- 

 ishment. In fact, deep-rooting is the rule beyond all 

 common expectation; thus almond roots the thick- 

 ness of one's thumb have been found at a depth of 22 

 feet one of the many instances of the characteristic 

 conditions of California agricultural practice 



Propagation is by both buds and grafts. The usual 

 practice is to bud the young stock in July and August, 

 and then in January and February following all those 

 which have not taken can be grafted, thus securing two 

 chances. When peach or almond is used as stock, 

 budding alone is done, as these stocks have been found 

 to take the graft poorly. The trees are not allowed to 

 remain in nursery longer than one year after budding, 

 and in many cases are set out the spring following, as 

 "dormant buds." In California the 

 necessity of deep and thorough prepa- 

 ration of the land before planting the 

 young trees cannot be too strongly em- 

 phasized ; for here the young tree 

 must have every facility for getting 

 its roots deeply and firmly established 

 at the beginning, in order to enable it 

 to withstand successfully the heat and 

 drought of the long, arid summer. 

 There has been much difference of 

 opinion as to the proper distance for 

 setting the trees apart and the mode 

 of laying out the orchard. In early 

 days the tendency was to rather close 

 planting, in some cases as close as 16 

 feet ; but experience soon demonstrated 

 the undesirability of too close proxim- 

 ity, and later plantings were made with 

 wider distances, until from 20 to 24 

 feet has come to be the rule. The lay- 

 ing out of orchards has caused much 

 discussion, some asserting that the 

 quincunx, hexagonal, and triangular 

 systems secure better use of the land 

 and allow better access to plow and 

 cultivator than do the planting in 

 squares. The square system, how- 

 ever, has come to be most generally used. The style 

 of tree was the next point of contention among the 

 growers; but experience soon decided in favor of the 

 low-headed tree of the vase-form, with rather more 

 branches than usual. The early, high-headed, sprawl- 

 ing trees have now practically disappeared from the 

 California orchards, notwithstanding the strong ob- 

 jections at first offered against the low trees on the 

 score of impeding easy cultivation. The prejudices 

 have been overcome by the appreciation of the many 

 advantages of a low, "stocky" tree, and the introduc- 

 tion of improved implements. The rule now is to cut 

 back the young trees at planting to from 18 to 24 inches. 

 Until the top is formed the stems are protected, by 

 whitewashing or wrapping with burlap, from the hot 

 afternoon sun. The first year from 3 to 5 branches are 

 allowed to grow from the stem, and these used to form 

 the main limbs of the tree. From this time the prun- 

 ing is done according to the usual methods for the 

 vase-form tree, with the exception perhaps that se- 

 verer cutting-back is practiced at first in order to give 

 strength and stockiness to the limbs. In California 

 the Plum is a most remarkable grower, often send- 

 ing out shoots 10 feet long in one season and prone 

 to overbear ; and when anything but the severest 

 shortening-in system during the first two seasons, at 

 least, is adopted, the trees very soon break down with 

 their loads of fruit. This has been emphasized again 

 and again in some of tne earlier improperly pruned 

 orchards, where even propping proved ineffectual; the 

 branches break at the bearing of the props, and when 

 they do not break are so badly damaged from sunburn 

 (to which the bark is extremely sensitive) that the tree 

 is irreparably injured. After the third or fourth sea- 

 son the growth of wood is much less and usually the 

 pruning operations are confined to keeping the tree in 



shape, removal of dead or damaged branches and short- 

 ening-in the current season's growth to keep the young 

 twigs in a vigorous growing condition and to prevent 

 overbearing. 



One interesting exception to the usual practice might 

 be mentioned here. On some very rich, moist bottom- 

 lands of the San Joaquin valley the long, slender 

 branches are not cut back ; in fact, they are encouraged 

 by pruning back to the crown. The long, arching "canes" 

 are allowed to remain until they have produced a crop 

 (which they do in the second season with the greatest 

 profusion), the ends resting upon the ground as the fruit 

 gains weight. When these droop too low, they are cut 

 back to the crown, when others will be produced to take 

 their places. In this way enormous crops of fruit are 

 produced on these lands, where, with ordinary treatment, 

 the trees would run entirely to wood. 



Thorough and persistent tillage is one of the first 

 principles of the California orchardist, for with him 



1856. Damson Plum (X 54). (See page 1373.) 



the absence of summer rains makes the conservation 

 of the winter rainfall an absolute necessity. Even 

 in the summer-irrigated districts the soil is tilled and 

 kept loose as soon as it is in proper condition, and no 

 weeds allowed to rob the trees of the precious fluid. Up 

 to three years ago, practically all the prune and Plum 

 crop was produced without summer irrigation. Winter 

 irrigation was often practiced and the water conserved in 

 the soil by the usual methods of tillage. But the season of 

 1897-8 was one of the driest in the history of the state, 

 with less than one-third of the usual amount of rainfall. 

 The use of summer irrigation was in some instances the 

 only salvation of the trees. The installation of pumping 

 plants and irrigation systems thereby received a great 

 impetus, until, to-day, many orchards of importance 

 are thus equipped, and the use of summer irrigation bids 

 fair to remain a permanent practice, at least in the pro- 

 duction of prunes. 



As yet the California Plum-grower (and this indeed is 

 generally true for all deciduous fruits) has hardly felt 

 the need of extensive fertilization. The soils of the arid 

 regions generally possess such high intrinsic fertility, 

 and the tree-roots have such great depths from which 

 to draw the nourishment and sustenance, that thus far 

 they have been able to produce the enormous crops taken 

 from the land without replenishment of the natural sup- 

 plies. In some of the older orchards, however, the need 

 of fertilization is beginning to be felt. In a great many 

 the main deficiency has been found to be vegetable mat- 

 ter, and, consequently, nitrogen. The extremely fine 

 tilth which has been maintained has resulted in the de- 

 struction of all natural green growth and the "burning 

 out " of the humus, and has necessitated the call for a 

 green-manure crop. This problem is rendered more dif- 

 ficult in California by the fact that any such crop must 

 be produced during the winter months and be ready to 



