How to Care for a Pistachio Tree

Pistachios are now grown in the United States.

Pistachio trees are becoming more popular in the United States and are being grown commercially in the San Joaquin Valley of California. Pollination is dependent on the wind, and most effective when a male tree is planted in the center, surrounded by female trees. If only a few trees are planted, plant female trees downwind of the male. Research on growing pistachio in the U.S. is just beginning, so cultivation practices are being adopted from growth habits in their native environments and on practices of similar nut trees.

Things You'll Need

• Male and female pistachio trees
• Shovel
• Stake, 1 1/2-inch-by-5 feet
• Pruning shears
• Ammonium sulfate
• Nutritional sprays

Instructions

1. Plant pistachios in well-drained soils with plenty of room to grow. Mature trees will be 20 to 30 feet tall. Commercial growers use a spacing of 17 to 24 feet apart.

2. Dig a hole 1-inch deeper than the root ball and three times as wide. Mix a superphosphate fertilizer into the soil according to package directions.

3. Carefully remove the plant from the container and plant undisturbed in the ground at a depth 1 inch deeper than it grew in the container. Backfill the hole and firm the soil. Water immediately.

4. Water pistachio trees during the late winter, spring and early summer. Pistachios need moist soil during these times for nut production. Stop regular irrigation in mid-August. Water deeply once or twice during the winter.

5. Drive a 5-foot stake into the ground approximately 6 inches from the tree on the upwind side. Tie the young tree to the stake so it develops a straight trunk as it grows.

6. Train the tree to a modified open vase shape during the first five years. Use heading cuts to keep branches growing outward. Pinching off the terminal bud of new shoots will encourage growth of lateral buds.

7. Develop three or four healthy branches spaced about 8 inches apart up the trunk during the second year. Remove other branches.

8. Select two healthy laterals at the end of each branch to form the secondary branches during the third year. Head these branches back to about 30 to 36 inches. Remove other branches.

9. Repeat the procedure in the fourth year, choosing two tertiary branches on each secondary and cutting them back to 30 to 36 inches. Continue pruning the tree in this manner in future years until the shape and framework of the tree are established.

10. Keep the center of the tree open to air and sunlight. Remove branches that head inward. Prune away branches below 4 feet from the ground.

11. Begin a schedule of fertilization in the second year. Apply 1/2 lb. of ammonium sulfate per tree in March and again in June. Increase the amounts to 1 lb. in the third year. In future years, apply between 1/2 and 1 lb. of ammonium sulfate per inch of trunk diameter. Water thoroughly after fertilizing.

12. Spray with a nutritional spray containing boron, copper and zinc with other minor elements monthly from April to July.

Tips & Warnings

• Nuts are ready for harvest in late August to early September beginning in the fourth or fifth year. Production will increase around year seven or eight with full production expected after 12 years.

References

• University of California: Pistachio Orchard Establishment
• New Mexico Agricultural Extension: Growing Pistachios in New Mexico