Pistacia

pistacia

( pih - STASH - ee - uh )

At-A-Glance Information

Commonly called Pistachio Tree or Pistache Tree, these evergreen and deciduous shrubs and trees need full sun to perform well. They reach between 25 and 30 feet tall and usually are seen just as wide, with deep green leaves. Foliage on deciduous species turns brilliant colors before dropping in fall. This genus includes both ornamental trees and fruiting species. Take care when planting Pistache trees in the landscape, as ingestion of plant parts can be toxic to animals. Pastachios also contain urushiol, the same irritant that is contained in Poison Ivy.

pistacia Species and Varietals

The genus Pistacia is a member of the plant family Anacardiaceae and includes 20 species. Pistacia growing zones vary depending on the species; for more information, see the descriptions below. To find your zone, click here: Zone Map.

Pistacia atlantica (Mount Atlas Pistache)
This species does well in zones 8-24 and is evergreen to semi-evergreen, depending on the climate. These trees are native to the Mediterranean, and reach 45-60 feet tall and wide. Fruit is dark blue to purple. These trees need good drainage and can tolerate desert heat and winds. No irrigation needed. This species is commonly used as an understock for Pistacia vera.

Pistacia chinensis (Chinese Pistache)
This deciduous ornamental species grows well in zones 4-23 and is native to China. It reaches 30-60 feet tall and equally as wide. Great fall color, even in milder climates. Varieties 'Keith Davey' and 'Pearl Street' are great male selections. This species can tolerate a wide range of watering, and can take relatively alkaline soils. Resistant to Oak Root Fungus. Great as a street tree, in lawns, over patios and amongst garden plantings.

Pistacia lentiscus (Mastic, Lentisk)
This species takes the form of an evergreen shrub or tree, and does best in zones 8, 9, and 12-24. These slowly reach 15-25 feet tall and 20-30 feet wide. Great as screening plants, they need little to no water once established. Can take poor soil and hot, dry locations in the garden. This species is harvested for its sap, which is the source of Mastic (an aromatic resin).

Pistacia mexicana (Mexican Pistache, American Pistachio, Wild Pistachio)
This species is native to Guatemala, Mexico, and the United States (in Texas). It is threatened due to habitat loss. Seeds produced by these species are very small.

Pistacia 'Red Push'
This deciduous species of tree grows in zones 8-24, and is a hybrid selection. These trees grow to reach 25-40 feet tall and 20-30 feet wide. Habit is broad and spreading. Foliage emerges red and then matures to green, turning red, orange and yellow in fall. Great as a street or lawn tree; needs moderate amounts of water to perform well.

Pistacia terebinthus (Terebinth, Turpentine Tree)
This species, native to Portugal, Morocco, Greece, and Turkey, this species forms a large shrub or small tree to 33 feet tall. Flowers are reddish-purple, and all parts of this plant have a strong resinous smell. The exudate of Terebinth Trees was the first product to be called Turpentine.

Pistacia vera (Pistachio)
This species of Pistache produces nuts, reaching 25-30 feet tall and about as wide. They can be either single- or multi-trunked trees, and grow best in zones 7-12, 14, 15, and 16-21. Nut production is best in zones 8-12; fruiting is unpredictable in other zones. Train these trees when young to get a good framework of branches that should begin about 4-5 feet off the ground.

Caring for and pruning pistacia Trees

Choose a place in the landscape that receives full sun. These trees will flower and subsequently fruit more profusely in this exposure. They should be receiving a minimum of 8 hours of sun each day. The ideal soil for pistachio trees is light, sandy, loamy and, of course, well-draining. These trees do not like to get their feet wet, so do not plant these trees in areas that flood regularly. Pistachio trees form long taproots that reach deep into the ground, and are considered to be very drought tolerant when mature. Pistache trees actually prefer somewhat arid landscapes, but still require a good amount of water during their flowering and fruiting seasons to produce well. Apply a thick layer of mulch around the base of trees to suppress weed growth, increase soil moisture retention, and help to regulate soil temperatures. Young trees should be watered regularly in order for them to develop a strong root system. Water established trees deeply but infrequently, allowing soil to dry out between waterings.

Pistachio trees can get by on applications of organic compost each year in spring to support their flowering and production for the year. IF trees seem to be struggling, are planted in particularly poor soil, or are not producing well, they may benefit from a feeding with a balanced, slow-release fertilizer applied in early springtime. Young trees should be pruned up to encourage a strong central leader to develop. Remove any branches that are growing directly across from each other, and leave branches that are spaced evenly around the trunk. Trim away any branches below the lowest main branch (which should be between 3 and 3 feet above the soil surface. All other branches should be pruned back to 4-6 inches in length. For mature trees, prune in the middle of summer to help encourage trees to branch and grow thicker.

Harvesting Pistachios
The main species used to harvest Pistachio nuts is Pistacia vera. These trees are dioecious, which means that male and female flowers are borne on separate trees. A male and female tree will need to be planted together in order to produce a harvest. Typically, one male pollinator is sufficient to pollinate around eight to ten female trees. The time for harvesting pistachios is when the hulls turn from reddish-yellow to light rose-yellow, and begin to split open. This typically happens in late summer into early fall, but harvesting time varies somewhat depending on where trees are grown. They can be shaken from the tree with a tarp or burlap laid on the ground underneath, and collected from there, or clipped from the tree. For small orchards or home gardens, hand harvesting is usually the preferred method. Commercial growers use mechanical harvesters which shake trees and catch nuts on a tarped deck. Gather all nuts and within 24 hours of harvesting, remove the shell. This will help to maintain the flavor and quality of the pistachios. Store shelled pistachios in airtight containers to protect them from moisture and air. They can be placed in a cool, dark pantry or cupboard, in the refrigerator for up to a year, or in the freezer for up to three years.

Propagation

Pistacia trees can be propagated either by using cuttings or from seed. To propagate your Pistache tree, follow the instructions below:

Propagating Pistacia by Cutting

Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.

Propagating Pistacia by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
Harvest your seeds. The seed pods on are pretty easy to spot, they're large and are left behind after flowers have faded. They are ready to be harvested once the hull separates from the inner shell and is easy to remove. The shell will change colors from reddish-yellow to rosy light yellow when ripe, which usually happens between late August and early October. Harvesting time can last for between 4 and 6 weeks. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.