Parodia magnifica aka Balloon Cactus

Parodia magnifica, or balloon cactus, is in the cactus family. Kew places its native range in Rio Grande do Sul, Brazil. Other sources say it also grows in nearby South American countries. It grows in hill grassland and cracks in rock walls. It also grows under larger plants in woods. The soil in these sites drains well and holds decayed plant matter. Its wild range is small, with gaps between patches.

Young plants have one round stem with blue-green skin. As stems age, they grow into short columns. They may also form clumps. The RHS gives garden height and spread as 0.3–1.6 feet [0.1–0.5 metres]. Chicago Botanic Garden reports heights up to 3 feet [0.91 metres]. Each stem is about 0.2–0.5 feet [0.07–0.15 metres] wide. It has 11–15 sharp, straight ribs. Areoles, the spots that bear spines, sit close together. They start white, then turn pale yellow. Their thin yellow spines bend and look like bristles. A shallow dip at the crown may change with age.

Several yellow flowers shaped like funnels can open near the stem tip. Each bloom spans about 0.16 feet [0.05 metres]. Chicago also records orange blooms. It gives the bloom season as May through August. LLIFLE reports that blooms return in warm weather, into early autumn. White wool and brown bristles cover each flower's base. Small, round pink fruits follow the flowers. They reach 0.03 feet [0.01 metres] across. The reddish-brown seeds feel rough and have tiny spines.

Grow this cactus in full sun or bright filtered light. Chicago and LLIFLE say some shade also suits it. Use cactus compost and a pot with plenty of drainage holes. The RHS lists acid or neutral soil as suitable. Give it modest amounts of water from mid-spring through late summer. Keep the compost just a little damp the rest of the year. During growth, feed every six to eight weeks. Use a liquid fertiliser low in nitrogen. Shelter it from frost; the RHS rates it H2. Chicago lists USDA zones 8–11, but it still needs frost-free care.

This plant suits pots, patios, greenhouses, and conservatories. Chicago also lists it for beds and borders. That garden says its flowers draw birds and butterflies. LLIFLE says it is easy to grow and grows fairly fast. The RHS gives five to ten years to reach full size. It needs no pruning, and growers can raise it from seed. Mealybugs may attack it. Aphids can appear while it blooms. The RHS reports few disease problems.