The nut trees require good drainage and a good supply of moisture. A reasonably fertile soil should be selected for a planting site but through mulches, manures, and commercial mineral fertilizers any soil may be built up to a high state of fertility. A weak tree has little chance and may come into bearing too late to be of value for the present owner. The annual growth should be checked each year and, unless 10 to 12 inches of growth has been made the previous year, some means of stimulating more growth should be employed. The hickory, pecan and black walnut, as a rule, make little new annual growth while the Persian or Carpathian walnut, heartnut and chestnut ordinarily produce good annual growth and an abundance of good foliage grown where it counts the most, on the new wood. Those who have observed the growth habits of nut trees know that the catkins are found on last year's growth, or two year old wood, and the fruiting flowers at the end of the present season's growth. There are times when the new growth developed in a matter of a few days to sometimes as long as two weeks. During the period of prolongation of the new growth and the formation and receptiveness of the pistillate flower much can happen. The catkins shed pollen when the temperature and atmospheric conditions are normal. Many times the pollen is dispersed before the pistillate flowers are formed. Cross vs Self-Pollination There is no assurance that a nut tree which fruits on the average of eight out of ten years will continue to do so in the future. Occasionally trees take on an alternate year bearing habit that could be caused from injury, insect or disease damage, or the relocation of plant food. The nut trees on their own roots should do better than when grafted or budded. The compatability of stock and scion is yet to be worked out and any constriction at the union may alter the fruiting habits.