When are plant and climate truly congenial? Perhaps the best test is the degree to which the plant spontaneously accommodates itself to all climatic conditions. Thus, the peach is ideally suited to climates in which it maintains itself without the aid of man. The peach is perfectly at home, then, in America only where it runs wild,--in parts of the South. In the North, East and the far West, peaches seldom grow spontaneously; and the cold of winter, the frosts of spring and the drouths of summer, in these regions, yearly remind us that notwithstanding the generations the tree has been grown in America it is still a stranger in a foreign country--an exotic from warm and sunlit Mid-Asia. Yet with a little help from man the peach takes kindly to many climates in which it does not grow spontaneously. Under what climatic conditions does the peach grow spontaneously? And under what climatic conditions can the peach be grown with the aid of man as a commercial success? These questions can be best answered by discussing the two constituents of climate, temperature and rainfall, in relation to the peach. Of the several phases of temperature only extremes in cold are determinants in peach-growing in New York. The peach stands for all that is tender and effeminate in a fruit-tree and fares so ill in winter's cold that the limits of peach-culture are set in all northern states by the winter climate. The undomesticated peach is at the mercy of the winter wherever the temperature falls below zero and seldom grows spontaneously where the mercury drops even to this point. By selecting hardy varieties and following careful cultural methods, however, peaches may be grown profitably in climates where it is occasionally as cold as ten degrees below zero. An isothermal line passing through points in New York where the thermometer marks -10° in an occasional winter sets the limits of peach-growing in New York. The red line in the accompanying map shows the territory in which peach-growing is reasonably safe in New York while the green line shows the outside limits of the industry as determined by cold. Even in the favored peach-regions of New York, winter-injury is a matter of vital importance to the peach-industry and growers seek means to avoid or check it. The problem is not an insurmountable one, for here and there are orchards and varieties which suffer little injury though possibly adjoining others in which trees or buds are wholly or partially killed. There must be reasons for the injury in the one and not in the other. These, the New York Agricultural Experiment Station made an attempt to discover a few years ago in letters addressed to the peach-growers of the State.[255] From the information received, and that gained by observation, we may lay down the following propositions regarding hardiness of the peach in New York.