Description
Pistachio growth habits
The pistachio is a broad, bushy, deciduous tree which grows
slowly to a height and spread of 25 to 30 feet, with one or
several trunks. The trees are inclined to spread and droop,
and may initially need staking. Their open habit and
attractive foliage make them valuable ornamentals. Under
favorable conditions pistachio trees live and produce for
centuries.
Foliage
The large, grayish leaves have 3 to 5 roundest, 2 to 4 inch-long leaflets.
pistachio flowers
Pistachios are dioeciously with male and female flowers on
separate trees. Male and female trees must be present for
fruit to set, or a branch from a male tree may be grafted on
a female tree. The small, brownish green flowers are without
petals and borne on maxillary racemes or panicles in early
summer. Wind carries the pollen from the male to the female
flowers.
pistachio fruit
The reddish, wrinkled fruits are borne in heavy clusters
somewhat like grapes. Although known as a nut, the fruit of
the pistachio is botanically a drupe, the edible portion of
which is the seed. The oblong kernel is about 1 inch in
length and 1/2 inch in diameter and protected by a thin,
ivory-colored, bony shell
Normally the shells split longitudinally along their sutures
when mature. Under unfavorable conditions during nut growth,
the shells may not split open.
The color of the kernel varies from yellowish through shades
of green, which extends throughout the kernel. In general
the deeper the shade of green, the more the nuts are
esteemed. Pistachio nuts are rich in oil, with an average
content of about 55%.
The trees begin bearing in 5 to 8 years, but full bearing is
not attained until the 15th or 20th year. Pistachios tend
toward biennial bearing, producing heavy crop one year
followed by little or none the next.
Production of nuts is also influenced by drought, excessive
rain, heat or cold and high winds.
