Stetsonia coryne aka Toothpick Cactus

Stetsonia coryne is a tree-like cactus called toothpick cactus. It belongs to the cactus family, Cactaceae. Its range includes Bolivia, Paraguay, northern Argentina, and western Brazil. It grows in dry plains and low mountains. Some stands grow near the edges of salt flats. It can form dense groves in the Chaco region. The species has Least Concern status on the IUCN list.

A short, thick trunk supports many stout, upright or arching branches. These branch again to form a wide crown. Sources report heights of 16–26 feet [5–8 metres]. LLIFLE gives a broader range of 10–33 feet [3–10 metres]. Neither source gives a separate range for garden plants. The stems have eight or nine blunt ribs with scalloped edges. Young growth has blue-green tones with a purple cast. Older stems turn olive green. The strong spines start white and darken to black. The longest reach about two to four inches.

Large white flowers have a pink tint and many stamens. They grow near the upper ends of the branches. Each bloom opens at night and lasts into the next morning. LLIFLE suggests bats may pollinate them, but this remains uncertain. Plants may take more than 25 years to flower. Bloom falls in spring or summer, with January and February reported. Fruit follows in autumn, with March and April reported. These months reflect the southern hemisphere. The egg-shaped fruit turns from green toward red.

Grow this cactus in a sunny site with good drainage. Use an open mineral potting mix that lets roots breathe. Wild plants tolerate clay and some salty soils. Plants in salty ground may look less healthy. In its hot, dry native climate, it survives occasional lows near −8°C. That report does not establish reliable hardiness in wet winters. Fresh potting mix may supply enough nutrients without added feed. LLIFLE limits feeding to summer and warns against feeding from September onward. Buffelgrass may threaten wild stands by promoting fire.

People grow this cactus as an ornamental and living fence. Its spines serve as needles, while trunks supply craft and furniture material. The fruit can be eaten raw or cooked. Its raw rind has a sharp, lemon-like taste. People seldom eat the seed-filled white pulp raw. The plant also has recorded medicinal uses, without clear details. One source reports mescaline but gives no measured amount. Its report of no known hazards does not establish general safety.