Pistachio, Pistacia: planting and care

Description and botany

The Pistacia, also known as pistachio, is a bush from the cashew family, just like cashew nuts and mango trees. It is sometimes considered to belong to a separate family, the pistacia family. This is a bush originating from temperate to tropical regions worldwide, mainly in Asia and around the Mediterranean basin, as far as Israel. The Pistacia genus includes around fifteen deciduous or evergreen species. Among them, we distinguish ornamental pistachio species from fruit-bearing pistachios like Pistacia vera, the true pistachio which is the only one producing the famous pistachios. The latter only bears fruit properly in regions with long, hot summers and will only thrive in the south of France. Do not confuse the pistachio with the Staphylea pinnata, also called false pistachio due to its edible seeds resembling pistachios. Between the true pistachio and the false pistachio, it’s not easy to tell them apart!

Pistacia lentiscus, illustration (1818)

Alongside the fruit-bearing pistachio, we also find ornamental pistachio species:

• The Pistacia terebinthus, the terebinth pistachio which is a deciduous species, one of the hardiest. Its bark exudes a resin (which gave its name to turpentine). This species also produces numerous clusters of small red edible fruits but with little taste.
• The Pistacia chinensis, this is the hardiest pistachio (-20°C). Its deciduous foliage turns red before falling in autumn.
• The Pistacia lentiscus, mastic tree or lentisk pistachio is a small tree native to our regions. It is spontaneous in Corsican scrub vegetation, along the Mediterranean coast, and as far as Charente-Maritime. It also produces an aromatic resin with many properties and small edible fruits.

Pistacia vera top left, Pistacia chinensis bottom left, and Pistacia lentiscus right

The pistachio forms a small tree with a bushy, rounded habit measuring between 2 and 10 m in height depending on the species. Its growth is relatively slow. Pistachios display great longevity and can live over 100 years.

This is a rather polymorphic tree or bush, generally wider than tall and, when planted in windy areas, it may adopt a more creeping habit. Its elegant branches are very ramified. The foliage is deciduous or evergreen depending on the species. It consists of alternate, petiolate leaves, imparipinnate in shape divided into 4 to 14 small ovate or elliptical-lanceolate leaflets, shiny and leathery. They can measure up to 20cm long. Their colour is a bright green, sometimes taking on reddish to purplish hues under the effect of cold. They have prominent veins. The evergreen leaves of Pistacia lentiscus resemble those of Laurustinus or Viburnum.

The Pistacia lentiscus and Pistacia terebinthus emit a powerful balsamic scent from the amber resin that escapes from their grey-orange bark. They exude a resin that hardens on contact with air called mastic in one (the renowned lentisk resin), turpentine in the other. The most sought-after mastic is that from lentisks originating from the Greek island of Chios. It has antiseptic properties and is also used in the manufacture of dental amalgams, confectionery, alcoholic beverages, pharmacology and perfumery.

Mastic tree on the island of Chios in Greece, where the mastic flowing from the trunks is harvested

Flowering occurs from March to May. It appears in the form of yellowish-green panicles of rather insignificant flowers. The pistachio is a dioecious tree, meaning there are male and female plants and it is necessary to have one of each sex to obtain fruits (1 male for 5 females).

Fruiting varies from one species to another and pollination from male trees to female trees is difficult in our climates. When the tree bears fruit, this flowering is followed by numerous small edible fruits. Fruiting of the true pistachio only occurs in warm regions and after 7 years of cultivation. In the true pistachio, the fruit is a drupe containing a shell that encloses an edible almond with a purple skin and green flesh: the pistachio which is then dried to be consumed as a dried fruit, as an appetiser, but also in pastries and confectionery. The Pistacia lentiscus and terebinthus also produce small edible drupes. They are grouped in clusters of small pea-sized fruits, first red then black at ripeness. They contain a small almond-shaped seed with a slightly sour and refreshing flavour. They can be eaten raw or pickled like capers.

The hard wood of the pistachio is used in marquetry, cabinet-making and carpentry.

Fruits of Pistacia lentiscus left, and right, fruits on the tree of Pistacia vera, which produces the pistachios we enjoy

Main species and varieties

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Planting the Pistachio Tree

Where to Plant It?

Native to the Mediterranean basin or the Middle East, the Pistacia thrives in warm climates and tolerates drought. It is a relatively frost-sensitive bush, preferring regions with mild winters. This is why it is mainly cultivated on the French Riviera. However, some species, such as the mastic bush, can withstand short frosts of around -12/-15°C once well-established, in well-drained soil and sheltered from prevailing cold winds. Bear in mind that north of the Loire, the pistachio bush has little chance of fruiting.

While the bush itself is not overly sensitive to cold, its flowering may be damaged by late frosts. In open ground, it is best suited to Mediterranean climates with hot, dry summers, with evergreen species being particularly well-adapted to summer heat and drought. Since it also tolerates sea spray, it is an excellent choice for coastal gardens.

Undemanding in terms of soil and exposure, it thrives in most conditions. It can grow in poor, stony, arid soil in dry climates or slightly acidic soil, though it prefers well-draining, chalky soils. Choose a warm, sunny spot, though it also tolerates partial shade.

The pistachio bush can be planted in dry gardens with a Mediterranean theme, in a shrub border, or even in a mixed hedge in mild climates, as its fruiting is highly decorative.

When to Plant It?

In regions with mild climates, the pistachio bush is best planted in early autumn, in September-October. In areas near its hardiness limit, spring planting is preferable.

How to Plant It?

The pistachio bush prefers well-draining soil. Allow a spacing of 7-10 m between two bushes.

• Loosen the soil deeply
• Soak the root ball for 1 hour in a bucket of water
• Dig a large hole at least 30 cm deep and wide
• Spread pumice, river sand, or gravel at the bottom of the planting hole
• Place the young plant in the centre of the hole with a stake
• Keep the pistachio bush upright and fill the hole with compost and sand mixed with the excavated soil, ensuring the collar remains above ground
• Firm the soil with your foot
• Water thoroughly after planting

A venerable mastic bush at the Selinunte site in Sicily (© Gwenaëlle David Authier)

Maintenance, pruning and care

The Pistacia is easy to cultivate in favoured regions where frost is neither severe nor prolonged. It only fears cold winters, especially when young. Once well-established, it will become increasingly drought-resistant. However, even though the pistachio tree is particularly drought-resistant, it requires regular watering during its growth period, especially to produce pistachios. In summer, be vigilant for the first 2-3 years after planting—water as soon as the soil is dry, but avoid waterlogging.

In autumn, fork in some compost around the base of the bush. Regularly hoe the soil with a fork to keep the base clean.

Wrap the crown of young pistachio trees with winter fleece in the first few years before the cold sets in to help them survive winter.

Pruning is minimal and helps maintain an attractive shape, even out growth, and control size. Prune only when necessary. A light annual shaping prune in late winter is sufficient to encourage branching:

• Remove dead or overcrowded wood
• Trim tangled branches
• Cut back inward-growing branches within the crown

Diseases and potential pests

The pistachio tree has a few known pests but they are rarely fatal. It may suffer from infestations of red spider mites. Spray in advance with nettle manure or a horsetail decoction. The foliage sometimes develops galls caused by the mite Eriophyes stefanii or the aphid Anopleura lentisci, but these do not threaten the life of your pistachio tree.

Propagation

The pistachio tree can be propagated by sowing, by semi-hardwood cuttings, or by grafting, a technique best suited to experienced or professional gardeners.

By sowing

This method is unpredictable.

• Collect fresh seeds in winter from female plants
• Soak them for a few days in water at room temperature
• Sow in winter in pots, outdoors in good seed compost

By propagation by cuttings

• In late summer, take stems around 15 cm long
• Remove the leaves from the lower part of the stems
• Place the cuttings in a well-draining substrate, made of a mix of compost and sand, kept moist
• Cover to maintain humidity
• Once the cuttings are well-rooted, transplant them into pots
• Plant out in the ground the following spring

Discover our guide: “Propagation by Cuttings: Everything You Need to Know About Different Techniques and Our Tips for Success”

Pairing the Pistachio Tree in the Garden

The Pistachio is an excellent plant for dry gardens, thriving in Mediterranean gardens and coastal areas. It can be planted in evergreen or deciduous hedges depending on the species, or in shrub borders. In a mixed hedge, it pairs well with Photinias, Elaeagnus ebbingei, laurustinus, or deciduous spindle bushes with stunning autumn colours. It can also weave through a hedge with fairly hardy, southern-inspired bushes like Buddleias and oleanders.

Mastic tree surrounded by oleander, Elaeagnus ebbingei, Buddleia, and laurustinus (Viburnum tinus)

In a shrub border, it thrives alongside Eucalyptus gunnii and Pittosporum. In mild climates, pair it with Olearia, Nandina, grevilleas, escallonias, or Choisya ternata.

Centre top: a mastic tree, accompanied here by Escallonia ‘Apple Blossom’, Eucalyptus gunnii, Olearia solandri ‘Aurea’, Pittosporum tenuifolium ‘Variegatum’, and Grevillea.