Cas (sour Costa Rican guava)
Psidium friedrichsthalianum
The sour guava of Costa Rican frescos; more cold- and wet-tolerant than common guava.
Hardiness: zones 10 to 12
Light: full sun
Size: about 20 ft tall, 15 ft wide
Harvest: March to October
From: Central America
Drought-hardy once established
Here: Too tender to overwinter outdoors on the Lake Erie shore (zone 6b to 7a): grow it in a pot and bring it in, or treat it as an annual.
Good for: food, wildlife.
Native to: Mexico, Central America & the Caribbean. Hardy in zones 10 to 12.
The story
Cas is Costa Rica's own guava, sour and aromatic, grown in every backyard from the Central Valley to the coasts and blended into the fresco de cas that comes with nearly every casado; it is native to the Pacific forests of Central America.
Planting
Full sun, any drained soil, warmth; it takes brief light frost. Plant a seedling; a small tree to 20 feet that bears in three years.
Growing
Water through dry spells; prune lightly after harvest. It is tougher than common guava.
Harvest and use
Pick when the skin turns yellow-green and the fruit gives slightly; too sour to eat fresh, it is blended with water and sugar into frescos, or cooked into jam.
What to watch for
Fruit fly, frost.
See if Cas (sour Costa Rican guava) fits your yard
Free planner: enter your ZIP for frost dates, climate fit and a sowing calendar. No account, no ads, no tracking cookies.
More tropical and subtropical food plants
General guidance, not professional advice. Conditions vary by yard and year; for local specifics ask your county extension office. Never eat a wild plant you cannot identify with certainty. Traditional uses are shared as history, not medical advice. © 2026 Sean Priest · Irie Orchard. Terms & credits · Privacy · Home