Opuntia sulphurea aka Airampu

Opuntia sulphurea is a low, shrubby cactus in the Cactaceae family. Its native range runs from Bolivia to Uruguay, including Argentina. It grows in deserts and dry shrublands. Wild plants occupy stony slopes and gaps in dry mountain scrub. They also grow in clay soils enriched by livestock. Its habitat extends from sea level to 11,483 feet [3,500 metres]. The species is widespread and holds Least Concern status.

This evergreen succulent forms broad clumps with spreading or upright branches. Plants reach about 1–1.3 feet [0.3–0.4 metres] tall. Their spread reaches 3.3–6.6 feet [1–2 metres]. Thick, flat stem segments give the plant its shape. Most segments measure 0.4–0.8 feet [0.12–0.25 metres] long. Reported extremes reach 0.26–0.98 feet [0.08–0.30 metres]. Their surfaces have clear bumps and lack hairs. The stems are green, though some take on purple tones. Segments at the branch tips break off with ease.

Small white areoles sit on the raised stem bumps. They bear dense, stiff spines, with one to eight per areole. These reach about 0.1–0.33 feet [0.03–0.10 metres] long. Most are straight, but some curve or twist. Young spines may look white or pink. Older ones can turn yellow, brown, red or grey. The plant bears yellow flowers about 0.13 feet [0.04 metres] long. Bees and other insects pollinate them. People gather its fruit for food and food colouring. The fruit also supplies dye for cloth.

In gardens, this cactus suits dry planting schemes with little irrigation. It withstands drought and needs little routine care. Sandy or gravelly soil works well when water drains freely. Clay can also work, provided it does not stay wet. The plant tolerates acid, neutral and alkaline soils. Its preferred pH range is 6–7.5. LLIFLE reports no major insect or disease problems. Growers can take stem cuttings during the growing season. The cut ends need time to callus before planting.

Tiny barbed glochids add a hazard beyond the larger spines. They break free on contact and lodge in skin. Their small size makes them hard to find and remove. Embedded glochids can cause marked irritation and pain. The documented food use concerns fruit, not a general safety claim.