Pistachio trees are members of the Anacardiaceae family and native to Asia. They are deciduous trees of small to medium size, growing only on average about 25 to 30 feet wide and usually just as tall, but some ornamental varieties can grow taller. If you wish to grow pistachio trees for their pistachios, note that only one variety produces these edible nuts. Plant your pistachio trees in the spring to give them a month or more to become established before the hottest days of summer begin.
Know which USDA plant hardiness zone you live in. This will help you decide which type of pistachio tree to buy. On the National Gardening Association website, you can look up your zone with your zip code, which may be easier than looking at a zone map.
Decide which kind of pistachio tree you wish to buy. Pistacia vera (zones 7b to 11) and Pistacia chinensis (zones 6b to 9b) are the two most common pistachio trees. The Pistacia vera is the only pistachio tree grown for its edible nuts. Pistacia chinensis (and other varieties) is grown as an ornamental shade tree and does not have edible nuts.
Calculate how many trees to buy to fit your space if you are buying more than one. Pistacia vera grows to be about 30 feet wide, so space them 60 feet apart to give them the most room possible to grow large and produce a large harvest. Pistacia chinensis can grow to a width of 35 feet, so space them about 70 feet apart if you want them to have room to reach their greatest mature width, or plant them closer, such as every 25 feet, to create a "woodsy" and more shaded area.
Select a nursery from which to purchase your pistachio trees. Local nurseries may sell pistachio trees, but it is a rare, so call prior to visiting there personally. Choose trees that appear to have healthy trunks and leaves (look on both sides). Alternatively, many online and catalog nurseries sell pistachio trees. Since you are buying sight unseen, look into whether the nursery is affiliated with the Better Business Bureau and check to see if their trees come with a warranty of any kind.