The plums of New York

by U. P. Hedrick

It is evident, if cross-fertilization is to play an important part in fruit-growing, in planting to secure it kinds must be chosen which come into blossom at the same time as those they are expected to fertilize. The table on [pages 106 to 109] shows the sorts that bloom together or nearly enough so to make cross-pollination possible. It will be found upon examining the table that, under normal conditions and during the average season, varieties of any one species overlap sufficiently for the above purpose unless it be the very early and very late varieties. Variations due to locality and to season must be expected but within the bounds of New York these will be slight. If the table is used for other regions than New York it must be borne in mind that the farther south, the longer the blossoming season; the farther north, the shorter the season. Properly interpreted the table of dates should be a useful guide as to the simultaneity of blooming.

Varieties of plums seem to have sexual affinities. That is, some varieties will fertilize each other very well and some will not, even though they belong to the same species. There seems to be little definite knowledge as to the sexual affinities of plums and it is not, therefore, possible to lay down exact rules for the selection of pollinizers for individual varieties. In the current discussions of cross-pollination it is probable that the importance of “affinities” is over-rated, and yet the subject is worthy of consideration. Waugh and Kerr have given this subject considerable attention for native and Japanese plums and have recommended a list of pollinizers for the several species.[149] The Domesticas and Insititias, the above writers hold, are best cross-pollinated by varieties from the same species if cross-pollination is essential.

The subject cannot be closed without the expression of the opinion that the lack of cross-pollination as a cause of the uncertainties in the setting of fruit has been over estimated in the planting of plum orchards. This expression of doubt is made because there are serious disadvantages in the planting of mixed orchards of any fruit and the question as to whether these do not outweigh the advantages must ever be considered.

LOCATIONS AND SOILS FOR PLUMS.

The plum is comparatively easy to suit in the matter of location of orchards, as is shown by the exceedingly wide range of this fruit in New York. Plums are grown with eminent success on the elevated and sloping lands adjoining the Great Lakes, the Central Lakes of western New York and on both banks of the Hudson. Unquestionably there are many other localities than those named about the waterways of the State and also upon the elevated lands in the western interior formed by morainic hills, and upon the slopes of the mountains in eastern New York. Upon any land in the State suited to general farm crops, where the severity of winter is tempered by the lay of the land or proximity to water, and where late spring frosts are infrequent, plums may be grown. The early blooming plums, the Trifloras in particular, require more or less consideration as to the slope of land, a northern exposure to retard blooming-time being best. With other species the direction of the slope makes little difference, though a slope for air and water drainage is always better than a dead level.

The plum is now thriving in New York, and in the country at large, in a great diversity of soils. The chief requisite for the genus in general seems to be good drainage. Given this condition, some sort of plums can be grown on almost any soil found in America not wholly prohibitive of plant growth. Plums can be found which will stand rather more water than any other of the tree-fruits, and since plums can be grafted on several stocks, each having its own adaptation to soils, the adaptability of the genus is still further increased. Yet the several species have somewhat decided soil preferences.

The Domesticas and Insititias, the plums now almost exclusively grown in New York, grow most satisfactorily, all things considered, on rich clay loams. The plum orchards in this State on such soils contain the largest and most productive trees and produce the choicest fruit from the standpoints of size, appearance and quality. Yet there are exceptions in which exceedingly fine Domestica plums are grown on light loams. The Station collection of about two hundred varieties of European plums is on stiff clay, but well drained, and the results are uniformly good. The Americanas and Nigras grow very well on much the same soils as the European sorts, speaking from the experience on the grounds of this Station, for varieties of these species are not generally grown in New York. Beyond question the Triflora plums, next most widely grown in New York after the Domesticas, are giving the best results on light soils—those most favorable for the peach. The ideal soil for this species is a sandy or gravelly loam but they are growing well on soils having either more sand or more clay than the ideal types. The Hortulana and Munsoniana plums incline to the comparatively light types of soils named as being best for the Trifloras rather than to the heavier lands on which the European plums are most commonly grown.

Plum-growers are well aware of the necessity of good drainage for this fruit but few seem to realize the importance of warmth in a plum soil. The plum, in common with all stone-fruits, grows best, as a rule, on soils having the power to absorb and retain heat, or if the soil have not these properties the location and the cultivation should be such as to provide as far as possible for “bottom heat.”

STOCKS AND PROPAGATION.

A discussion of stocks naturally follows one of soils, for the two are intimately related. The plum can be successfully grown on various stocks and for this reason the practices of nurserymen are diverse, depending upon the cost of the stocks, the ease with which they may be budded or grafted and the adaptability of the tree to the stocks. Unfortunately there is little experimental data to show which of the several stocks is best for the different plums and since growers seldom know what stocks their plums are growing upon they can give almost no information as to the desirability of propagating on this stock or that. Nurserymen know the stocks best adapted to their purpose and from them we have sought information.