Psidium friedrichsthalianum (Costa Rica Cas Fruit)

Psidium friedrichsthalianum, commonly known as Costa Rican Guava or Cas Guava, is an evergreen shrub or small tree in the Myrtaceae family, native to Central America, particularly Costa Rica, Nicaragua, and Panama. It grows in humid tropical and subtropical forests and their margins, often reaching 10-20 feet tall in cultivation. The leaves are opposite, elliptic to oblong, leathery, and glossy green, with prominent lateral veins. Fragrant white flowers have numerous conspicuous stamens and develop into rounded, yellow fruits, usually one to two inches across. The pale, juicy pulp is intensely acidic and aromatic, with numerous hard seeds. Unlike sweeter guavas, Cas is primarily used for refreshing drinks, juices, sorbets, and preserves, often with added sugar.

Psidium friedrichsthalianum prefers full sun to partial shade, warm, humid conditions, and fertile, well-drained, slightly acidic soil. Regular watering is important, especially during flowering and fruit development. The species is less tolerant of drought and cold than common guava (Psidium guajava). It is best suited to USDA Zones 10-11 and should be protected from frost. Container cultivation is possible where winter protection is necessary. The fruits are particularly popular in Costa Rica, where they are used to prepare fresco de cas, a traditional sweetened fruit drink.

See Article about Guava Tree.

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