Strawberry tree

Arbutus unedo

1. Identification and origin

The strawberry tree (Arbutus unedo L.), belonging to the Ericaceae family, is a shrubby or arboreal species typical of the Mediterranean region and the Atlantic coast of Western Europe. It is native to Portugal, Spain, France, Italy, Greece and North Africa. The species is part of the understorey of montados, scrublands and Mediterranean forests, being highly adapted to poor soils and drought conditions. It is valued for its fruits (arbutus berries), used in the production of spirits, preserves and artisanal products, and for its ecological role in soil conservation and biodiversity.

2. Economic importance

The strawberry tree has growing economic importance in Portugal, especially for:

• Production of arbutus spirit, with a strong tradition in the Centre and South of the country.
• Production of fresh or frozen fruits for preserves, jellies and pastry.
• Production of strawberry tree honey, of high commercial value.
• Reforestation and recovery of degraded areas, due to its resilience to fire and drought.

The species has potential for expansion in agroforestry systems and sustainable production in Mediterranean regions.

3. Botanical characterisation

An evergreen shrub or small tree, 2–8 m tall, with a rounded crown and reddish bark that peels off in plates. The leaves are simple, leathery, lanceolate, with serrated margins and dark-green colour. The flowers are white or pinkish, urn-shaped, grouped in hanging panicles. The fruits are globose, rough berries, initially green, turning yellow and then red when ripe. Ripening is slow and occurs in autumn, frequently coinciding with flowering. The root system is deep and well adapted to poor and stony soils.

4. Soil and climate requirements

The strawberry tree adapts well to Mediterranean climates, with hot and dry summers and mild winters. It tolerates light frosts and prolonged periods of drought. It prefers acidic to slightly acidic soils (pH 5.0–6.5), well-drained, poor or moderately fertile. It does not tolerate waterlogging. It is a heliophilous species, but tolerates partial shade. It shows high resilience to fire, sprouting vigorously after fires.

5. Main pests

• Strawberry tree weevil (Curculio elephas): Boreholes and damage to fruits.
• Fruit fly (Ceratitis capitata): Attacks on ripe fruits.
• Scale insects (Coccoidea): Honeydew and sooty mould on leaves and branches.
• Mites (Tetranychus spp.): Chlorosis and reduction of photosynthesis.
• Defoliating caterpillars (Noctuidae): Damage to young leaves.
• Nematodes (Meloidogyne spp., Pratylenchus spp.): Root decline and lower vigour.

6. Main diseases

• Leaf spot (Septoria unedonis): Circular lesions and premature leaf fall.
• Cankers (Botryosphaeria spp.): Necrosis on branches and crown decline.
• Root rots (Phytophthora cinnamomi): Wilting and death of plants in poorly drained soils.
• Powdery mildew (Erysiphe spp.): White coating on young leaves.
• Anthracnose (Colletotrichum spp.): Lesions on leaves and fruits, especially in humid conditions.

7. General crop management

It includes the choice of plants adapted to the local climate, planting in well-drained soils, weed control in the early stages, formation and cleaning pruning to improve air circulation and reduce diseases. Monitoring of strawberry tree weevil, fruit fly and Phytophthora is essential. Harvesting of the fruits should be carried out when they reach an intense red colour and soft texture, being quickly processed due to their perishability.

Bibliographic references

• EPPO Global Database. Arbutus unedo – pests and diseases.
• CABI Invasive Species Compendium. Arbutus unedo – datasheets.
• Correia, A. C., et al. (2018). Ecology and management of Arbutus unedo. Forest Systems.
• Celikel, G., & Demirsoy, L. (2019). Arbutus species: Botany and uses. Acta Horticulturae.
• Ribeiro, M. M., et al. (2016). Genetic resources and domestication of Arbutus unedo in Portugal.