The Chinese Pistache Tree (Pistacia chinensis) is a beautiful shade and autumn ornamental tree that has been referred to as a “touch of New England to sunsets” with their brilliant red and orange fall foliage. They have an incredible tolerance to almost any soil type. The pistache is also great for growth near patios and sidewalks as they have deeply grown root systems. An intermediate growth speed of roughly 13 to 24 inches yearly that performs best in growing zones 6-9 and will reach a mature height and width of 25-35 feet.
Choosing a location: Your pistache tree will benefit best from a location that receives full sun and a well draining, fertile soil. The trees have long taproots and need at least a 15 foot clearance from structures so their canopy can stretch out. Soil pH can be important but with these trees, good drainage trumps the soil acidity. To be sure there is appropriate drainage, dig a 1 foot deep by one foot wide hole in your intended planting location. Fill the hole with water, and wait one hour. If the water has fully drained, then the location is good. If there is water being retained, you may want to plant elsewhere or create a raised bed for the tree.
1) Once you have found an ideal location for the tree, make your hole 4-5 times as wide as the root ball.
2) Gently comb the roots with your hands to free them up for the best soil contact.
3) Be sure to center your tree and begin to back fill the hole, tamping the soil down as you fill to prevent air pockets from forming.
4) Water thoroughly and spread 2-3 inches mulch around the base of the tree. Be sure not to let the mulch too close to the trunk to avoid fungus from forming.
Watering: For the first month be sure to water your pistache tree twice weekly. By the fifth week, monitor the soil and only water if the top one inch of soil has become dry. Due to the pistache having such a deep taproot you’ll need to water generously. The best way to ensure that you’re watering deeply enough is to place your garden hose next to the base of the tree on a trickle. Leave the hose running for about 30 minutes. The slow trickle will prevent the water from beading off and it will have a chance to soak deeply into the soil to reach the taproot.
Pruning: If your pistache tree is 5 years or younger then it will need some trimming to encourage its trademark umbrella-like canopy. Prune the top of the tree when it reaches six feet tall between January and February and this will force more branches to develop. As branches emerge, select one as the tree’s trunk, the other as a branch and remove the rest. The trunks should be left to grow another three feet and then prune those to 2 feet above your original cut which in turn will encourage more branches. Repeat this process until the pistache has a well spaced, symmetrical look.
*TIP* Pruning is vital as the trees can get to be a bit “leggy” in their early years before forming into the expected oval shape. Also be sure to rake around the base of the tree in the late autumn season to remove leaf litter.
Fertilizing: For pistache trees that are 5 years (or younger), fertilizer should be introduced during the spring and fall seasons. Use a nitrogen based formula with superphosphate if the tree has not grown at least 2-3 feet annually. Be sure to follow the application instructions provided on the packaging.
The gender of the pistache tree can be difficult to determine at times. If there are two different genders near one another, the female will produce unnoticeable green blossoms that turn into brilliant red clumps of berries in the fall season. As winter approaches, the berry color will change into a blue/purple that attracts a multitude of birds. The bark can be appealing to the sight as well. If peeled from the tree, it reveals a beautiful salmon pink interior color.