Mastic tree

How to recognise it

Growth habit

Dense, rounded, evergreen shrub of 1–3 m, sometimes a small tree of 5–8 m in the wild. In a pot it usually stays at 1–2 m.

Leaf

Alternate, divided into an even number of leaflets, so with no terminal leaflet: 3–6 pairs of leathery, glossy dark green leaflets of 1–5 cm on a narrowly winged leaf stalk.

Flower

Tiny and without petals, in dense clusters in the leaf axils, in April–May. Male and female flowers grow on separate plants; the male ones stand out with their red anthers. The wind takes care of pollination.

Fruit

Round little drupe of 4–5 mm, red at first, black when ripe, in clusters. Only female plants bear fruit, and only with a male plant nearby.

Stem

Young twigs reddish, older branches with grey bark. A wound releases sticky, fragrant resin.

Confusion with

Terebinth (Pistacia terebinthus) loses its leaves in winter and each leaf has a terminal leaflet. Myrtle has simple, opposite leaves and white flowers.

Flowering: April–May · Pruning: April

Why grow it?

• Evergreen, glossy foliage that looks fresh all year: a fine alternative to the olive in a large pot.
• The leaves and twigs smell pleasantly of resin when you crush them.
• Very drought-tolerant: a rewarding patio plant for a sunny, warm spot.
• Takes pruning well, so you can shape it into a ball, a low hedge or a small standard.
• In its homeland, warblers, thrushes and other birds eat the fruits in autumn and winter.
• A plant with a long history: the resin of the mastic tree has been harvested since ancient times.

Mastic tree: where does it grow best?

• In the wild: maquis and garrigue, dry slopes, rocks and coastal areas around the Mediterranean, often close to the sea.
• In the garden: full sun in a warm, sheltered spot. It tolerates sea wind and salt.
• Dry, free-draining soil, chalky or neutral; poor soil is fine. Wet feet in winter are fatal.
• Here it is safest in a large pot moved to a frost-free place in winter. In open ground only in the mildest spots, against a south-facing wall.

Goes well with

• Olive: The same Mediterranean feel and the same care: group them together on the patio.
• Rosemary: Fragrant leaves and early blue flowers for bees, in the same dry spot.
• Lavender: Grey leaves and purple summer flowers beside the dark, glossy green.
• Myrtle: Another evergreen shrub of the maquis, with fragrant leaves and white flowers.
• Rock rose: Cistus has papery flowers in June and the same love of dry, poor soil.

Mastic tree: when and how to plant it?

1. Buy it in a pot from a nursery or garden centre that sells Mediterranean plants. Never bring plants or cuttings back from the wild on holiday: you may also spread diseases and pests.
2. Choose a roomy pot with a drainage hole and put a layer of gravel or crocks in the bottom.
3. Use compost for Mediterranean plants, or ordinary potting compost mixed with a third of gravel or coarse sand.
4. Move it outdoors in May, after the last night frost, to the sunniest spot on the patio.
5. Water well after planting, then let the compost dry out almost completely between waterings.
6. In open ground: plant in May against a south-facing wall in gravelly soil, and accept that a harsh winter may kill it.

Care

Water

In a pot, every few days in warm weather, but let the compost dry out in between. Hardly any in winter.

Feeding

In a pot, a little organic fertiliser once a month from April to July. Not needed in open ground.

Overwintering

From November to April, keep the pot in a bright, cool, frost-free place at 0–10 °C, such as an unheated greenhouse or a cool, light stairwell.

Repotting

Every two to three years in spring, into a slightly larger pot with fresh compost.

Wintering outdoors

If it stays outside, stand the pot against a south-facing wall under an overhang and cover it with horticultural fleece in hard frost.

Tip: Overwinter it too cold rather than too warm: in a bright place at 0–10 °C it stays compact and healthy, while in a heated living room it grows weak and attracts scale insects.

Pruning and mowing

Pruning months: April.

When: In April, when it goes back outside; a light trim in summer if needed.

How:

• Cut out dead and frost-damaged twigs back to healthy wood.
• Shorten long shoots to keep the shrub compact; it regrows well, even from older wood.
• For a small standard, gradually remove the lower side branches and let a crown develop at the top.
• Wear gloves if you prune a lot: the sticky resin clings to your hands.

Caution: Do not prune in autumn: the new, soft shoots would then freeze in winter.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

Sow fresh black fruits in autumn or spring in a pot in a warm place. Red fruits often contain no viable seed.

Cuttings

Semi-ripe cuttings of 10 cm in July–August, under plastic in a warm spot. They root slowly and not always.

Mastic tree: how does it get through the winter?

Hardy to −10 °C: protect in harsh winters.

• Evergreen: the glossy leaves stay on the plant all year.
• Tolerates a short spell of light frost, down to about −10 °C, but not prolonged frost in wet soil.
• In a pot it overwinters in a bright, cool, frost-free place with very little water.
• After a harsh winter, a frozen plant often regrows from the base: wait until June before you give up on it.

Diseases and pests

• Frost damage: Brown leaves and dead twigs after winter. Wait until May, then cut out the dead wood.
• Root rot: Caused by compost that is too wet, especially in winter. Use free-draining compost and a pot with a hole, and water sparingly.
• Scale insects: Small brown bumps and sticky leaves, especially when overwintered indoors. Wipe them off with a soft brush or cloth and put the plant back outside in spring.
• Red spider mite: Dull, speckled leaves in a dry, warm room. Provide fresh air and spray the foliage with water.

Through the year

• January: Overwinter cool and bright; very little water.
• March: Gradually water a little more. Watch for scale insects.
• April: Prune and shape. Inconspicuous flowers. Put outside by day in mild weather.
• May: Outdoors for good after the last night frost. Repot or plant.
• June: A little fertiliser once a month. Water in warm weather.
• July: Take semi-ripe cuttings. Water.
• August: Water in dry spells; no more fertiliser.
• October: Collect and sow black fruits, if there are any.
• November: Bring indoors to a bright, cool, frost-free place.
• December: Overwintering. Water only when the pot is bone dry.

Did you know?

• On the Greek island of Chios, mastic has been harvested for centuries: the bark is scored and the resin that dries into clear ‘tears’ is collected. The know-how of this cultivation has been on UNESCO’s list of intangible cultural heritage since 2014.
• Mastic was already chewed in ancient times. The Greek word for the resin is linked to a verb meaning to chew, and via Latin this gave English the word masticate.
• The pistachio nut comes from a related species, Pistacia vera; the mastic tree itself bears no edible nuts.