Say it: TEF-roh-cactus. Common names: paper spine cactus, pine cone cactus, snowman cactus.
Where it grows
The dry Andean foothills of western Argentina, in rocky scrub at altitude where winters are cold and dry. T. geometricus comes from Catamarca; T. articulatus, T. aoracanthus and T. weberi from the same region of Argentina.
Size and growth
Opuntia relatives that grow as chains of round or egg-shaped segments stacked on each other. Geometricus has smooth, nearly spineless grey-purple balls like a stack of snowballs; articulatus has pine-cone segments with flat, papery spines (the diadematus form); aoracanthus carries long stout spines; weberi forms low clumps with yellowish spines. Slow growers that add a segment or two a year. Segments detach easily and root where they fall.
Flowers
White or pale pink flowers from the tips of segments in spring and summer, large and silky for the size of the plant. Geometricus flowers are especially pretty.
Care
- Light: full sun.
- Water: sparingly in summer, bone dry in winter.
- Soil: very gritty.
- Cold: hardy to around 15°F if dry — they want a cold, dry winter.
From segments and seed
Segments root easily. Seed is the hard way: the large, corky seeds have tough coats and germinate slowly and unevenly, often taking months, with many seeds sprouting only in the second year. Soaking, nicking the coat and alternating warm and cool spells all help. Expect around half to germinate at best.
T. geometricus seeds · T. geometricus seedling · T. articulatus seeds · T. aoracanthus seeds · T. aoracanthus segment · T. weberi plant