182 Wisconsin State Horticultural Society. 



Immature wood is that in which development is not complete. 

 "We have all seen a midsummer growth arrested by slight frost, 

 which brought death to all exposed succulent growths, 'ihe same 

 degree of cold after a ripening period of a month would have sim- 

 ply hastened a more perfect maturity. Herein lies the chief diffi- 

 culty of successful fruit-growing in Minnesota. Soil too rich in 

 humus and retentive of water, which, with their warm autumns 

 prolonging the growth up to the sudden check of their polar 

 winter, and all unprepared, the tree cannot endure the trial. The 

 tree must have its fluids well condensed before the severe frosts of 

 winter come. Now, that soil which will — other things being 

 equal — produce the most perfect growth of foliage and wood of 

 the finest texture, that is hardened or ripened as made, will most 

 surely produce the condition called " hardy." 



Climate. — I mean by this not latitude, but temperature and 

 saturation (moisture). Death is caused not so much by the 

 extreme of cold as by the relative conditions of the plant at its 

 advent. There is no .fixed degree of cold which kills a given 

 variety or species. We may say of any given person or plant, that 

 a certain degree of cold will almost assuredly cause death; but we 

 may not say how much greater cold the same object may endure if 

 specially prepared for the trial. We learn this from human life 

 and the more delicate of plant life. M. De Candolle, the eminent 

 vegetable scientist quoted before, says "that the northern limit of 

 a plant is not determined by excess of cold, but by want of heat;" 

 meaning that if the heat and other conditions of growth and ma- 

 turity are perfect, a plant may be grown indefinitely beyond its 

 present limit with safety. The cooler and dryer the climate in 

 which a good growth can be attained, the more perfect the wood 

 and the more cold it will endure. Plant-life requires the greatest 

 saturation in extreme heat and least in extreme cold. A high tem- 

 perature must have a greater degree of moisture to sustain life 

 than a low one in summer, but there must be a ripening season cor- 

 responding with the extent and force of the growing season, or the 

 plant will not be prepared for winter. There must be, therefore, a 

 perfect balance of the elements of growth, heat, moisture and food. 



Evenness of temperature or exemption from sudden transitions, 

 is another condition. The reverse action, mentioned before, of 



