The plums of New York

by U. P. Hedrick

Plum trees in New York are set from twelve to twenty feet apart. The amount of room given seems to depend mostly upon the custom in the locality, though, as all agree, it should depend upon the soil and the variety. The deduction which plum-growers are drawing from these experiences is that the plum should have more room than is generally given it, therefore, wider plantings are more the rule now than formerly. Little attention has been paid to mixed planting for cross-pollination in this State, as the Domesticas are planted almost exclusively and seem under orchard conditions to be self-fertile.

In this region plum trees are usually planted two years from the bud, the exception being the Japanese which are sometimes set at a year from the bud. Plum trees in the past have been headed at three or four feet above the ground but the tendency now is to head them lower—half the above distances, and in orchards so planted there seems to be no inconvenience in tilling with modern implements. In the commercial orchards of the State the heads are formed of four or five main branches and in the case of the Domesticas and Insititias about a central trunk but with the Trifloras the leader is often removed leaving a vase-formed head. After the head is formed the subsequent pruning is simple, consisting of cutting out injured and crossed branches and heading-in long, whip-like growths. The Trifloras receive more pruning than the European varieties, as much of the fruit is borne on the growth of the previous season and it is necessary to keep the bearing wood near the trunk. It is the custom to cut rank growing Trifloras severely but the value of such a procedure is doubtful, as the more such a plum is pruned the more it will need pruning in the years to follow. A better plan seems to be to curtail the food and prune as little as possible, though on rich soils the tree would probably grow out of all bounds unless cut back somewhat year after year.

About the only cultivated native plums to be found in New York, if a few Wild Goose trees here and there are excepted, are on the grounds of this Station. Experience here demonstrates that, prune as you will, certain varieties of the native species will remain crooked, ungainly and unkempt. Pruning some varieties is necessary in order to permit pickers to get into the dense, thorny heads; heading-in such varieties would make their tops wholly impenetrable.

In common with all tree-fruits the best plum orchards are tilled. Such tillage usually consists of plowing in the spring followed by frequent cultivation until the middle of August, at which time a cover-crop of clover, oats or barley is sown. The plum seems to require more water than other tree-fruits—it often thrives in comparatively moist land and fails on sandy soils where the peach would grow luxuriantly. Cultivation to save moisture is very necessary for the plum in the experience of New York growers. Grass and grain have proved ruinous in most orchards where tried, though cultivated crops between young trees to pay for keep until fruiting-time are very generally planted. The claim is made by some, and with a show of reason, that there is less of the brown-rot in tilled orchards than in neglected ones for the reason that the mummied fruits which carry the fungus through the winter are buried by plowing and with shallow cultivation, at least, do not come to light and life.

Plum-growers very generally recognize the several distinct and valuable purposes which cover-crops serve in orchards. They protect the tree from root-killing, from cold, keep the soil from washing, add humus and, with legumes, nitrogen to the soil, modify the physical structure of the soil and hasten seasonal maturity of the tree. There is one other function which is not so often taken into account. Plum orchards in which cover-crops are regularly grown, even though the crop be not a legume, need less fertilizers than those in which no such crop is grown. There are several reasonable suppositions as to why there should be such an effect, but one not usually given sufficient consideration is that cover-crops make available much plant food in the soil. Each plant in the crop collects food from soil and air, most of it otherwise unavailable, and turns it over to the trees.

A discussion of fertilizers naturally follows. Present practices in the use of fertilizers with the plum, as with other fruits, are very diverse. It is impossible to ascertain what considerations have governed the applications of fertilizers in the plum orchards of New York or what the results have been. Too often, it is to be feared, fertilizers have been used as “cure-alls” for any or all of the ills to which trees are heirs. Out of the mass of conflicting data as to the effects of fertilizers on plums, the most apparent fact is that much of the fertilizers for this fruit is wasted; this in face of the fact that plums want rich soils. But the plum crop is mostly water, the foliage remains on the ground, the trees grow several years before fruiting, their growing season is from early spring until late fall, the roots go deep and spread far, the trees transpire large amounts of water, hence may thrive on diluted solutions of plant food, and now and then there is an off year in bearing for the trees to recuperate.

It does not follow from the above consideration that plums never need fertilizers, but it does seem plain that they need rather less than truck or farm crops and that applications of plant food must be made with exceedingly great care if fertilizing is to be done without waste. There is a growing disposition on the part of plum-growers to experiment very carefully and know that they are getting the worth of their money before using any considerable quantity of fertilizers for their trees.

Thinning the fruit should be a regular practice with plum-growers, but it is the operation in the growing of this fruit about which growers are most careless both as to whether it is done at all and in the manner of doing. Many growers in New York, realizing the great necessity of thinning certain varieties of Triflora, as Burbank and Abundance, follow the practice very regularly with plums of this group; but the Domesticas are seldom well thinned, though some of them, of which Lombard is a conspicuous example, ought nearly always to have anywhere from one-fifth to half of the fruit removed. Growers of some of the native varieties in regions where these sorts are grown say that under cultivation some kinds of these plums will bear themselves to death if a part of the crop be not removed in most years. Those growers in New York who thin, do the work as soon as possible after the June drop has taken place.

HARVESTING AND MARKETING.

Plum trees in this climate begin to bear when set from three to five years. The Triflora varieties will bear soonest, the Old World varieties next in order, say at four years from setting, and the native sorts, as a rule, come in bearing last. At eight or ten years of age, prolific varieties of the Triflora and Domestica sorts bear in a good year about three bushels of fruit; the Insititia and native varieties, on the Station grounds, at least, do not bear as much, though most of the plums of these two groups bear more regularly than the first named groups.