Pistachio trees are dioecious, which means that male and female flowers happen on different trees. For fruit set, the pollen from the male tree must travel through the wind to land on the female flowers. One male tree can pollinate between 6 and 9 female trees.
Pistachio female and male trees will flower at the same time if they have had require 37 days of days below 7 degrees during the winter/spring period. If there are not enough cold days, the male trees will flower first. If this occurs, the pollen can be collect from the males to be used on the female flowers at a later date.
Male trees are normally taller and more robust than female trees, growing between 6- 10m. They have a strong root system with a tap root. They thrive in areas with long, hot summers and will grow on a variety of soil types. Addition of Dolomite lime will be beneficial before planting. Little pruning is required.